server: libxtreemfs for Java unit test: Close all obtained file handles....

server: libxtreemfs for Java unit test: Close all obtained file handles. Otherwise, an assertion at shutdown is violated.

git-svn-id: https://xtreemfs.googlecode.com/svn/trunk@3549 f8528748-c2c0-11dd-ba5c-d3b7c2b3b534