perf config: Refactor a duplicated code for obtaining config file name

We were doing the same sequence to figure out what is the config
pathname to use, fix it by doing it before those two uses.

Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1493209268-5543-2-git-send-email-treeze.taeung@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-config.c

@@ -159,6 +159,7 @@ int cmd_config(int argc, const char **argv)
 	int i, ret = 0;
 	struct perf_config_set *set;
 	char *user_config = mkpath("%s/.perfconfig", getenv("HOME"));
+	const char *config_filename;
 
 	argc = parse_options(argc, argv, config_options, config_usage,
 			     PARSE_OPT_STOP_AT_NON_OPTION);
@@ -175,6 +176,11 @@ int cmd_config(int argc, const char **argv)
 	else if (use_user_config)
 		config_exclusive_filename = user_config;
 
+	if (!config_exclusive_filename)
+		config_filename = user_config;
+	else
+		config_filename = config_exclusive_filename;
+
 	/*
 	 * At only 'config' sub-command, individually use the config set
 	 * because of reinitializing with options config file location.
@@ -192,13 +198,9 @@ int cmd_config(int argc, const char **argv)
 			parse_options_usage(config_usage, config_options, "l", 1);
 		} else {
 			ret = show_config(set);
-			if (ret < 0) {
-				const char * config_filename = config_exclusive_filename;
-				if (!config_exclusive_filename)
-					config_filename = user_config;
+			if (ret < 0)
 				pr_err("Nothing configured, "
 				       "please check your %s \n", config_filename);
-			}
 		}
 		break;
 	default:
@@ -221,13 +223,8 @@ int cmd_config(int argc, const char **argv)
 
 				if (value == NULL)
 					ret = show_spec_config(set, var);
-				else {
-					const char *config_filename = config_exclusive_filename;
-
-					if (!config_exclusive_filename)
-						config_filename = user_config;
+				else
 					ret = set_config(set, config_filename, var, value);
-				}
 				free(arg);
 			}
 		} else