Add the port of libibverbs/examples/rc_pingpong.c to libfabric.

Signed-off-by: Arun C Ilango <arun.ilango@intel.com>
Moved rc_pingpong.c to a seperate directory to keep only simple clean examples in the simple directory.
Also fixed completion queue length.

Signed-off-by: Arun C Ilango <arun.ilango@intel.com>
Add prefix fi_ to rc_pingpong executable.

Signed-off-by: Arun C Ilango <arun.ilango@intel.com>
Merge pull request #1 from a-ilango/rc_pingpong

Add the port of libibverbs/examples/rc_pingpong.c to libfabric.