Move test_pkt_util.cc to lib.
Fix memory leak in test_xmpp_discovery.

Bug# https://bugs.launchpad.net/opencontrail/+bug/1349308

Change-Id: I04820ca68d54cf430444f33af72bd183b5774c11
Merge "Move test_pkt_util.cc to lib. Fix memory leak in test_xmpp_discovery."