dapl scm: Adding socket cm provider for better scalability on large homogeneous clusters.

dapl scm: Adding socket cm provider for better scalability on large homogeneous clusters.

Bring socket cm provider back to life with some changes:

better threading support for exchanging QP information.
Avoid blocking during connect to support dynamic connection
model with MPI implementations.

consumer control of ack timeout/retries.

disconnect/reject capabilities via socket exchange.

version support for wire protocol to insure compatibility
with peer scm provider. Add gids to exchange.

validated with Intel MPI on a 14,000+ core fabric using IB DDR.

Signed-off by: Arlin Davis ardavis@ichips.intel.com