Check for NULL before trying to use the variable.

This commit was SVN r14444.

ompi/mca/pml/ob1/pml_ob1_start.c

@@ -32,11 +32,11 @@ int mca_pml_ob1_start(size_t count, ompi_request_t** requests)
 
     for(i=0; i<count; i++) {
         mca_pml_base_request_t *pml_request = (mca_pml_base_request_t*)requests[i];
+        if(NULL == pml_request)
+            continue;
         if (OMPI_REQUEST_PML != requests[i]->req_type) {
             continue;
         }
-        if(NULL == pml_request)
-            continue;
 
         /* If the persistent request is currently active - obtain the
          * request lock and verify the status is incomplete. if the