Bugfix for possible race in rdmacm_destroy_dummy_qp

This commit was SVN r22245.

ompi/mca/btl/openib/connect/btl_openib_connect_rdmacm.c

@@ -1158,10 +1158,16 @@ static int rdmacm_disconnected(id_context_t *context)
  */
 static int rdmacm_destroy_dummy_qp(id_context_t *context)
 {
-    if (NULL != context->id->qp) {
-        ibv_destroy_qp(context->id->qp);
-        context->id->qp = NULL;
+    /* We need to check id pointer because of retransmitions.
+                               Maybe the reject was already done. */
+
+    if (NULL != context->id) {
+	    if (NULL != context->id->qp) {
+           ibv_destroy_qp(context->id->qp);
+           context->id->qp = NULL;
+        }
     }
+
     if (NULL != context->contents->dummy_cq) {
         ibv_destroy_cq(context->contents->dummy_cq);
     }