vlib: fix out of memory issue

'show node foo' causes infinite loop resulting in out of memory.
This patch fixes the issue by breaking the loop on invalid input.

Ticket: VPP-1538
Type: fix
Fixes: 98afc711c5
Change-Id: Icf2be92e277a7f820d4e08bea9ef22ffbbb116f6
Signed-off-by: Filip Tehlar <ftehlar@cisco.com>

src/vlib/node_cli.c

@@ -562,6 +562,9 @@ show_node (vlib_main_t * vm, unformat_input_t * input,
       else
 	error = clib_error_return (0, "unknown input '%U'",
 				   format_unformat_error, line_input);
+
+      if (error)
+	break;
     }
 
   unformat_free (line_input);