Exclude javassist from curator-test in test scope of pom file to prevent...

Exclude javassist from curator-test in test scope of pom file to prevent error in unit test of tachyon.hadoop.TFSTest.

>>mvn --version output.

Apache Maven 3.2.1 (ea8b2b07643dbb1b84b6d16e1f08391b666bc1e9; 2014-02-14T12:37:52-05:00)
Maven home: /usr/local/Cellar/maven/3.2.1/libexec
Java version: 1.8.0, vendor: Oracle Corporation
Java home: /Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/jre
Default locale: en_US, platform encoding: UTF-8
OS name: "mac os x", version: "10.9.4", arch: "x86_64", family: "mac"

>> mvn install, output error Message:

Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.366 sec <<< FAILURE!
tachyon.hadoop.TFSTest  Time elapsed: 0.366 sec  <<< ERROR!
java.lang.IllegalStateException: Failed to transform class with name tachyon.client.TachyonFS. Reason: java.io.IOException: invalid constant type: 18
	at javassist.bytecode.ConstPool.readOne(ConstPool.java:1113)
	at javassist.bytecode.ConstPool.read(ConstPool.java:1056)
	at javassist.bytecode.ConstPool.<init>(ConstPool.java:150)
	at javassist.bytecode.ClassFile.read(ClassFile.java:765)