This commit fixes a performance regression introduced by the request
rework. We were always using the multi-thread path because
OPAL_ENABLE_MULTI_THREADS is either not defined or always defined to 1
depending on the Open MPI version. To fix this I removed the
conditional and added a conditional on opal_using_threads(). This path
will be optimized out in 2.0.0 in a non-thread-multiple build as
opal_using_threads is #defined to false in that case.
Fixesopen-mpi/ompi#1806
Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>
544adb9aed