See https://fedorahosted.org/fesco/ticket/1185 for details. My patch is at https://bitbucket.org/dhiru/redhat-rpm-config/branch/strict-format URL.
Hi Panu, Can we please push this change as soon as possible?
-Werror=format-security added in redhat-rpm-config-9.1.0-55.fc21, for the better or worse...