Don't count failed include attempts against the configuration include level. (issue #9593 reported by mostyn)

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.2@61958 65c4cc65-6c06-0410-ace0-fbb531ad65f3

config.c

@@ -966,6 +966,8 @@ struct ast_config *ast_config_internal_load(const char *filename, struct ast_con
 
 	if (result)
 		result->include_level--;
+	else
+		cfg->include_level--;
 
 	return result;
 }