perf config: Modify size factor of snprintf

According to definition of snprintf, it gets size factor including
null('\0') byte.  So '-1' is not neccessary. Also it will be helpful
unfied style with other cases. (eg. builtin-script.c)

Signed-off-by: Sihyeon Jang <uneedsihyeon@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20181201154603.10093-1-uneedsihyeon@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/config.c

@@ -815,14 +815,14 @@ int config_error_nonbool(const char *var)
 void set_buildid_dir(const char *dir)
 {
 	if (dir)
-		scnprintf(buildid_dir, MAXPATHLEN-1, "%s", dir);
+		scnprintf(buildid_dir, MAXPATHLEN, "%s", dir);
 
 	/* default to $HOME/.debug */
 	if (buildid_dir[0] == '\0') {
 		char *home = getenv("HOME");
 
 		if (home) {
-			snprintf(buildid_dir, MAXPATHLEN-1, "%s/%s",
+			snprintf(buildid_dir, MAXPATHLEN, "%s/%s",
 				 home, DEBUG_CACHE_DIR);
 		} else {
 			strncpy(buildid_dir, DEBUG_CACHE_DIR, MAXPATHLEN-1);