osc/pt2pt: do not drop/reacquire the ompi_request_lock

This lock is now recursive so it is safe to call into the pml without
dropping the lock.

Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>

ompi/mca/osc/pt2pt/osc_pt2pt_data_move.c

@@ -1622,8 +1622,6 @@ static int ompi_osc_pt2pt_callback (ompi_request_t *request)
     size_t incoming_length = request->req_status._ucount;
     int source = request->req_status.MPI_SOURCE;
 
-    OPAL_THREAD_UNLOCK(&ompi_request_lock);
-
     assert(incoming_length >= sizeof(ompi_osc_pt2pt_header_base_t));
     (void)incoming_length;  // silence compiler warning
 
@@ -1667,8 +1665,6 @@ static int ompi_osc_pt2pt_callback (ompi_request_t *request)
     osc_pt2pt_gc_add_request (module, request);
     ompi_osc_pt2pt_frag_start_receive (module);
 
-    OPAL_THREAD_LOCK(&ompi_request_lock);
-
     OPAL_OUTPUT_VERBOSE((50, ompi_osc_base_framework.framework_output,
                          "finished posting receive request"));