Fix test and update travis.yml 

I tried to run `mvn clean install` on my PC, and build failed.

```
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO] 
[INFO] ActiveAndroid - Parent ............................ SUCCESS [0.121s]
[INFO] ActiveAndroid ..................................... SUCCESS [1.696s]
[INFO] ActiveAndroid - Tests ............................. FAILURE [7.837s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 10.669s
[INFO] Finished at: Sun Nov 24 23:18:31 JST 2013
[INFO] Final Memory: 28M/242M
[INFO] ------------------------------------------------------------------------
```

I fixed the code for pass the test, and updated travis.yml to observe the test result in Travis.

Travis's log are as follows. 

```
[INFO] emulator-5554_test_unknown_sdk :   Running instrumentation tests in com.activeandroid.test
[INFO] emulator-5554_test_unknown_sdk :     Run started: com.activeandroid.test, 37 tests:
[INFO] emulator-5554_test_unknown_sdk :       Start [1/37]: com.activeandroid.test.CacheTest#testAndroidTestCaseSetupProperly
[INFO] emulator-5554_test_unknown_sdk :       End [1/37]: com.activeandroid.test.CacheTest#testAndroidTestCaseSetupProperly
[INFO] emulator-5554_test_unknown_sdk :       Start [2/37]: com.activeandroid.test.CacheTest#testGetTableInfos
[INFO] emulator-5554_test_unknown_sdk :       End [2/37]: com.activeandroid.test.CacheTest#testGetTableInfos
[INFO] emulator-5554_test_unknown_sdk :       Start [3/37]: com.activeandroid.test.ConfigurationTest#testAndroidTestCaseSetupProperly
[INFO] emulator-5554_test_unknown_sdk :       End [3/37]: com.activeandroid.test.ConfigurationTest#testAndroidTestCaseSetupProperly
[INFO] emulator-5554_test_unknown_sdk :       Start [4/37]: com.activeandroid.test.ConfigurationTest#testCreateConfigurationWithMockModel
[INFO] emulator-5554_test_unknown_sdk :       End [4/37]: com.activeandroid.test.ConfigurationTest#testCreateConfigurationWithMockModel
[INFO] emulator-5554_test_unknown_sdk :       Start [5/37]: com.activeandroid.test.ConfigurationTest#testDefaultValue
[INFO] emulator-5554_test_unknown_sdk :       End [5/37]: com.activeandroid.test.ConfigurationTest#testDefaultValue
[INFO] emulator-5554_test_unknown_sdk :       Start [6/37]: com.activeandroid.test.query.DeleteTest#testAndroidTestCaseSetupProperly
[INFO] emulator-5554_test_unknown_sdk :       End [6/37]: com.activeandroid.test.query.DeleteTest#testAndroidTestCaseSetupProperly
[INFO] emulator-5554_test_unknown_sdk :       Start [7/37]: com.activeandroid.test.query.DeleteTest#testApplicationTestCaseSetUpProperly
[INFO] emulator-5554_test_unknown_sdk :       End [7/37]: com.activeandroid.test.query.DeleteTest#testApplicationTestCaseSetUpProperly
[INFO] emulator-5554_test_unknown_sdk :       Start [8/37]: com.activeandroid.test.query.DeleteTest#testDelete
[INFO] emulator-5554_test_unknown_sdk :       End [8/37]: com.activeandroid.test.query.DeleteTest#testDelete
[INFO] emulator-5554_test_unknown_sdk :       Start [9/37]: com.activeandroid.test.query.DeleteTest#testFrom
[INFO] emulator-5554_test_unknown_sdk :       End [9/37]: com.activeandroid.test.query.DeleteTest#testFrom
[INFO] emulator-5554_test_unknown_sdk :       Start [10/37]: com.activeandroid.test.query.FromTest#testAll
[INFO] emulator-5554_test_unknown_sdk :       End [10/37]: com.activeandroid.test.query.FromTest#testAll
[INFO] emulator-5554_test_unknown_sdk :       Start [11/37]: com.activeandroid.test.query.FromTest#testAndroidTestCaseSetupProperly
[INFO] emulator-5554_test_unknown_sdk :       End [11/37]: com.activeandroid.test.query.FromTest#testAndroidTestCaseSetupProperly
[INFO] emulator-5554_test_unknown_sdk :       Start [12/37]: com.activeandroid.test.query.FromTest#testApplicationTestCaseSetUpProperly
[INFO] emulator-5554_test_unknown_sdk :       End [12/37]: com.activeandroid.test.query.FromTest#testApplicationTestCaseSetUpProperly
[INFO] emulator-5554_test_unknown_sdk :       Start [13/37]: com.activeandroid.test.query.FromTest#testAs
[INFO] emulator-5554_test_unknown_sdk :       End [13/37]: com.activeandroid.test.query.FromTest#testAs
[INFO] emulator-5554_test_unknown_sdk :       Start [14/37]: com.activeandroid.test.query.FromTest#testGroupByHaving
[INFO] emulator-5554_test_unknown_sdk :       End [14/37]: com.activeandroid.test.query.FromTest#testGroupByHaving
[INFO] emulator-5554_test_unknown_sdk :       Start [15/37]: com.activeandroid.test.query.FromTest#testJoinTypes
[INFO] emulator-5554_test_unknown_sdk :       End [15/37]: com.activeandroid.test.query.FromTest#testJoinTypes
[INFO] emulator-5554_test_unknown_sdk :       Start [16/37]: com.activeandroid.test.query.FromTest#testJoins
[INFO] emulator-5554_test_unknown_sdk :       End [16/37]: com.activeandroid.test.query.FromTest#testJoins
[INFO] emulator-5554_test_unknown_sdk :       Start [17/37]: com.activeandroid.test.query.FromTest#testLimit
[INFO] emulator-5554_test_unknown_sdk :       End [17/37]: com.activeandroid.test.query.FromTest#testLimit
[INFO] emulator-5554_test_unknown_sdk :       Start [18/37]: com.activeandroid.test.query.FromTest#testLimitOffset
[INFO] emulator-5554_test_unknown_sdk :       End [18/37]: com.activeandroid.test.query.FromTest#testLimitOffset
[INFO] emulator-5554_test_unknown_sdk :       Start [19/37]: com.activeandroid.test.query.FromTest#testOffset
[INFO] emulator-5554_test_unknown_sdk :       End [19/37]: com.activeandroid.test.query.FromTest#testOffset
[INFO] emulator-5554_test_unknown_sdk :       Start [20/37]: com.activeandroid.test.query.FromTest#testOrderBy
[INFO] emulator-5554_test_unknown_sdk :       End [20/37]: com.activeandroid.test.query.FromTest#testOrderBy
[INFO] emulator-5554_test_unknown_sdk :       Start [21/37]: com.activeandroid.test.query.FromTest#testSingleJoin
[INFO] emulator-5554_test_unknown_sdk :       End [21/37]: com.activeandroid.test.query.FromTest#testSingleJoin
[INFO] emulator-5554_test_unknown_sdk :       Start [22/37]: com.activeandroid.test.query.FromTest#testWhereNoArguments
[INFO] emulator-5554_test_unknown_sdk :       End [22/37]: com.activeandroid.test.query.FromTest#testWhereNoArguments
[INFO] emulator-5554_test_unknown_sdk :       Start [23/37]: com.activeandroid.test.query.FromTest#testWhereWithArguments
[INFO] emulator-5554_test_unknown_sdk :       End [23/37]: com.activeandroid.test.query.FromTest#testWhereWithArguments
[INFO] emulator-5554_test_unknown_sdk :       Start [24/37]: com.activeandroid.test.query.SelectTest#testAndroidTestCaseSetupProperly
[INFO] emulator-5554_test_unknown_sdk :       End [24/37]: com.activeandroid.test.query.SelectTest#testAndroidTestCaseSetupProperly
[INFO] emulator-5554_test_unknown_sdk :       Start [25/37]: com.activeandroid.test.query.SelectTest#testApplicationTestCaseSetUpProperly
[INFO] emulator-5554_test_unknown_sdk :       End [25/37]: com.activeandroid.test.query.SelectTest#testApplicationTestCaseSetUpProperly
[INFO] emulator-5554_test_unknown_sdk :       Start [26/37]: com.activeandroid.test.query.SelectTest#testFrom
[INFO] emulator-5554_test_unknown_sdk :       End [26/37]: com.activeandroid.test.query.SelectTest#testFrom
[INFO] emulator-5554_test_unknown_sdk :       Start [27/37]: com.activeandroid.test.query.SelectTest#testSelectAll
[INFO] emulator-5554_test_unknown_sdk :       End [27/37]: com.activeandroid.test.query.SelectTest#testSelectAll
[INFO] emulator-5554_test_unknown_sdk :       Start [28/37]: com.activeandroid.test.query.SelectTest#testSelectDistinct
[INFO] emulator-5554_test_unknown_sdk :       End [28/37]: com.activeandroid.test.query.SelectTest#testSelectDistinct
[INFO] emulator-5554_test_unknown_sdk :       Start [29/37]: com.activeandroid.test.query.SelectTest#testSelectDistinctColumns
[INFO] emulator-5554_test_unknown_sdk :       End [29/37]: com.activeandroid.test.query.SelectTest#testSelectDistinctColumns
[INFO] emulator-5554_test_unknown_sdk :       Start [30/37]: com.activeandroid.test.query.SelectTest#testSelectEmpty
[INFO] emulator-5554_test_unknown_sdk :       End [30/37]: com.activeandroid.test.query.SelectTest#testSelectEmpty
[INFO] emulator-5554_test_unknown_sdk :       Start [31/37]: com.activeandroid.test.query.SelectTest#testSelectStringColumns
[INFO] emulator-5554_test_unknown_sdk :       End [31/37]: com.activeandroid.test.query.SelectTest#testSelectStringColumns
[INFO] emulator-5554_test_unknown_sdk :       Start [32/37]: com.activeandroid.test.query.UpdateTest#testAndroidTestCaseSetupProperly
[INFO] emulator-5554_test_unknown_sdk :       End [32/37]: com.activeandroid.test.query.UpdateTest#testAndroidTestCaseSetupProperly
[INFO] emulator-5554_test_unknown_sdk :       Start [33/37]: com.activeandroid.test.query.UpdateTest#testApplicationTestCaseSetUpProperly
[INFO] emulator-5554_test_unknown_sdk :       End [33/37]: com.activeandroid.test.query.UpdateTest#testApplicationTestCaseSetUpProperly
[INFO] emulator-5554_test_unknown_sdk :       Start [34/37]: com.activeandroid.test.query.UpdateTest#testUpdate
[INFO] emulator-5554_test_unknown_sdk :       End [34/37]: com.activeandroid.test.query.UpdateTest#testUpdate
[INFO] emulator-5554_test_unknown_sdk :       Start [35/37]: com.activeandroid.test.query.UpdateTest#testUpdateSet
[INFO] emulator-5554_test_unknown_sdk :       End [35/37]: com.activeandroid.test.query.UpdateTest#testUpdateSet
[INFO] emulator-5554_test_unknown_sdk :       Start [36/37]: com.activeandroid.test.query.UpdateTest#testUpdateWhereNoArguments
[INFO] emulator-5554_test_unknown_sdk :       End [36/37]: com.activeandroid.test.query.UpdateTest#testUpdateWhereNoArguments
[INFO] emulator-5554_test_unknown_sdk :       Start [37/37]: com.activeandroid.test.query.UpdateTest#testUpdateWhereWithArguments
[INFO] emulator-5554_test_unknown_sdk :       End [37/37]: com.activeandroid.test.query.UpdateTest#testUpdateWhereWithArguments
[INFO] emulator-5554_test_unknown_sdk :     Run ended: 9319 ms
[INFO]   Tests run: 37,  Failures: 0,  Errors: 0
[INFO] emulator-5554_test_unknown_sdk :   Report file written to /home/travis/build/rejasupotaro/ActiveAndroid/tests/target/surefire-reports/TEST-emulator-5554_test_unknown_sdk.xml

[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO] 
[INFO] ActiveAndroid - Parent ............................ SUCCESS [0.838s]
[INFO] ActiveAndroid ..................................... SUCCESS [19.077s]
[INFO] ActiveAndroid - Tests ............................. SUCCESS [38.231s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1:11.279s
[INFO] Finished at: Sun Nov 24 05:29:31 UTC 2013
[INFO] Final Memory: 24M/157M
[INFO] ------------------------------------------------------------------------
```