libibverbs/tests: fix buffer overrun issue that caused random connection failures

libibverbs/tests: fix buffer overrun issue that caused random connection failures

libibverbs tests occasionally had failures connecting over sockets in order to exchange QP information.  (The ping-pong tests failed more than the perftests.)  The failure was caused by copying a port number into a buffer that was too small, then using it to look up an address.  Increase the size of the buffer and make sure that it's NULL terminated.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
git-svn-id: svn://openib.tc.cornell.edu/gen1/trunk@1447 ad392aa1-c5ef-ae45-8dd8-e69d62a5ef86