After a time of executing unit tests, get posix_memalign failed.

[jdellithorpe]

posix_memalign is a method used for allocating memory. This method is failing with the following error:

posix_memalign(4096, 134283264) failed: /home/jdellit/RAMCloud/src/Infiniband.h:353 (RegisteredBuffers)

This might be due to a memory leak across JNI, like #1

[jdellithorpe]

Issue #1's fix 5b8e5d4 did not fix this problem.