When 'mca_oob_send_callback' accesses the callback 'orte_pls_rsh_terminate_job_cb'

with an error status (< 0) then the req buffer is NULL. Put checks around the
OBJ_RELEASE(req) calls so that we don't try to release NULL :/

This commit was SVN r10641.

orte/mca/pls/base/pls_base_proxy.c

@@ -143,6 +143,7 @@ static void orte_pls_rsh_terminate_job_cb(
     int rc;
     if (status < 0) {
         ORTE_ERROR_LOG(status);
+        if(NULL != req)
             OBJ_RELEASE(req);
         return;
     }
@@ -150,6 +151,8 @@ static void orte_pls_rsh_terminate_job_cb(
     if (0 > (rc = orte_rml.recv_buffer_nb(peer, ORTE_RML_TAG_RMGR_CLNT, 0, orte_pls_rsh_terminate_job_rsp, NULL))) {
         ORTE_ERROR_LOG(rc);
     }
+
+    if(NULL != req)
         OBJ_RELEASE(req);
 }