Merge pull request #2796 from vcoxvco/fix_unninit

libarchive/archive_util.c: Uninitialized variable

(cherry picked from commit 1cd0b9179c)

libarchive/archive_util.c

@@ -456,7 +456,7 @@ __archive_issetugid(void)
 		return (-1);
 	if (ruid != euid || ruid != suid)
 		return (1);
-	if (getresgid(&ruid, &egid, &sgid) != 0)
+	if (getresgid(&rgid, &egid, &sgid) != 0)
 		return (-1);
 	if (rgid != egid || rgid != sgid)
 		return (1);