There is a potential race condition in MPI_Init() where an orte even
thread could be in a function that uses OPAL_THREAD_LOCK /
OPAL_THREAD_UNLOCK when ompi_mpi_init calls opal_set_using_threads().
Closesopen-mpi/ompi#1586
Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>