backend: Handle RPC errors

Use the new RPC error reporting interface to report RPC errors from
plugins.

Signed-off-by: Corey Minyard <minyard@acm.org>

apps/backend/backend_client.c

@@ -723,7 +723,7 @@ from_client_edit_config(clixon_handle h,
             }
         }
         if ((ret = candidate_commit(h, NULL, "candidate", myid, 0, cbret)) < 0){ /* Assume validation fail, nofatal */
-            if (netconf_operation_failed(cbret, "application", clixon_err_reason())< 0)
+            if (clixon_plugin_report_err(h, cbret) < 0)
                 goto done;
             xmldb_copy(h, "running", "candidate");
             goto ok;