drop unneeded BuildRequires: gdb
originally added to log build-time tool crashes
commit 4cfeb5ea50361f16f7eb5a7faf71493f929ef980
Author: Caolán McNamara <caolanm@redhat.com>
Date: Sat Apr 25 13:53:26 2015 +0100
get gdb to put bt into build log on failure