Fix crash when dialplan remove include is called with too few arguments.

"dialplan remove include x from y" crashed when the amount of arguments
was less than 6.

(closes issue ASTERISK-18762)
Reported by: Andrey Solovyev
Tested by: Andrey Solovyev
........

Merged revisions 343936 from http://svn.asterisk.org/svn/asterisk/branches/1.8


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/10@343944 65c4cc65-6c06-0410-ace0-fbb531ad65f3

pbx/pbx_config.c

@@ -87,7 +87,7 @@ static char *handle_cli_dialplan_remove_include(struct ast_cli_entry *e, int cmd
 		return complete_dialplan_remove_include(a);
 	}
 
-	if (strcmp(a->argv[4], "from"))
+	if (a->argc != 6 || strcmp(a->argv[4], "from"))
 		return CLI_SHOWUSAGE;
 
 	if (!ast_context_remove_include(a->argv[5], a->argv[3], registrar)) {