change source url

Signed-off-by: Toshaan Bharvani <toshaan@powerel.org>

SPECS/autoconf213.spec

@@ -4,7 +4,7 @@ Version:    2.13
 Release:    48%{?dist}
 License:    GPLv2+
 URL:        http://www.gnu.org/software/autoconf/
-Source:     ftp://prep.ai.mit.edu/pub/gnu/autoconf/autoconf-%{version}.tar.gz
+Source:     https://ftp.gnu.org/gnu/autoconf/autoconf-%{version}.tar.gz
 Patch0:     autoconf-2.12-race.patch
 Patch1:     autoconf-2.13-mawk.patch
 Patch2:     autoconf-2.13-notmp.patch