usnic: Fix configure.ac typo
usnic: unify teardown between trunk and v1.8 branches

Make the del_procs, module finalize, and endpoint destructors be the
same between trunk and v1.8, with one exception: the very beginning of
v1.8 module_finalize calls del_procs for each proc to simulate/pretend
the trunk/v1.9 PML behavior of calling del_procs before module_finalize.
usnic: Fix connectivity checker pointer mismatch

Ensure that the connectivity checker agent only uses pointers from the
client that is the same process as the agent.

Not necessary for the v1.8 branch -- this is a trunk/v1.9-only problem.