Fix the test code of testUpdateWithPGobject, for cannot update ResultSet

The test testUpdateWithPGobject still failed due to other 2 issues below:

The ResultSet cannot be updated.
Fixed by initialize statement with flag "CONCUR_UPDATABLE".

    [junit] Testcase: testUpdateWithPGobject(org.postgresql.test.jdbc2.ResultSetTest):  Caused an ERROR
    [junit] ResultSets with concurrency CONCUR_READ_ONLY cannot be updated.
    [junit] org.postgresql.util.PSQLException: ResultSets with concurrency CONCUR_READ_ONLY cannot be updated.
    [junit]     at org.postgresql.jdbc2.AbstractJdbc2ResultSet.isUpdateable(AbstractJdbc2ResultSet.java:1583)
    [junit]     at org.postgresql.jdbc2.AbstractJdbc2ResultSet.checkUpdateable(AbstractJdbc2ResultSet.java:2840)
    [junit]     at org.postgresql.jdbc2.AbstractJdbc2ResultSet.updateValue(AbstractJdbc2ResultSet.java:3208)
    [junit]     at org.postgresql.jdbc2.AbstractJdbc2ResultSet.updateObject(AbstractJdbc2ResultSet.java:1244)
    [junit]     at org.postgresql.jdbc2.AbstractJdbc2ResultSet.updateObject(AbstractJdbc2ResultSet.java:1570)
    [junit]     at org.postgresql.test.jdbc2.ResultSetTest.testUpdateWithPGobject(ResultSetTest.java:743)
    [junit]

After issue above was fixed, will encounter "No primary key" issue when trying to update the table.
Fixed by setting primary key for test table "testpgobject".

    [junit] Testcase: testUpdateWithPGobject(org.postgresql.test.jdbc2.ResultSetTest):  Caused an ERROR
    [junit] No primary key found for table testpgobject.
    [junit] org.postgresql.util.PSQLException: No primary key found for table testpgobject.
    [junit]     at org.postgresql.jdbc2.AbstractJdbc2ResultSet.isUpdateable(AbstractJdbc2ResultSet.java:1651)
    [junit]     at org.postgresql.jdbc2.AbstractJdbc2ResultSet.checkUpdateable(AbstractJdbc2ResultSet.java:2840)
    [junit]     at org.postgresql.jdbc2.AbstractJdbc2ResultSet.updateValue(AbstractJdbc2ResultSet.java:3208)
    [junit]     at org.postgresql.jdbc2.AbstractJdbc2ResultSet.updateObject(AbstractJdbc2ResultSet.java:1244)
    [junit]     at org.postgresql.jdbc2.AbstractJdbc2ResultSet.updateObject(AbstractJdbc2ResultSet.java:1570)
    [junit]     at org.postgresql.test.jdbc2.ResultSetTest.testUpdateWithPGobject(ResultSetTest.java:744)
    [junit]


The  Jdbc2TestSuite can finally full pass now.

  runtest:
      [mkdir] Created dir: /home/kingter/pgjdbc/build/testresults
      [junit] Testsuite: org.postgresql.test.jdbc2.Jdbc2TestSuite
      [junit] Tests run: 337, Failures: 0, Errors: 0, Time elapsed: 67.633 sec