performance: also include ACTION_PING_REPLY messages in results

This means that the throughput is twice what it was since
replies were not accounted for previously.

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
build: don't use MPI on Xeon Phi for tests

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>