vty: Return error if cmd returns CMD_WARNING while reading cfg file

Otherwise bad configurations can easily sneak in and produce unexpected
behavior.

Change-Id: Ic9c1b566ec4a459f03e6319cf369691903cf9d00
diff --git a/src/vty/command.c b/src/vty/command.c
index a36f30a..6a9d18a 100644
--- a/src/vty/command.c
+++ b/src/vty/command.c
@@ -2631,8 +2631,7 @@
 		ret = cmd_execute_command_strict(vline, vty, NULL);
 		cmd_free_strvec(vline);
 
-		if (ret != CMD_SUCCESS && ret != CMD_WARNING
-		    && ret != CMD_ERR_NOTHING_TODO) {
+		if (ret != CMD_SUCCESS && ret != CMD_ERR_NOTHING_TODO) {
 			if (indent) {
 				talloc_free(indent);
 				indent = NULL;