Changes all synchronization primitives to be dynamically allocated. This
should help catch any subtle errors in pthread lifecycles.
This change also pre-initializes synchronization primitives before
threads begin to run, eliminating a potential race condition that
probably would have caused a segfault on startup on a very fast box.
Also changes mutex and condition variable allocations to use
MTYPE_PTHREAD and updates tests to do the proper initializations.
Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>