RPM: Add new subpackage for PAC responder
It was discovered that duplicating files in two subpackages is not
permitted by Fedora packaging guidelines[1]. This patch moves the PAC
responder to a new sssd-common-pac subpackage that both the sssd-ipa
and sssd-ad subpackages will require.
[1] https://fedoraproject.org/wiki/Packaging:Guidelines?rd=Packaging/Guidelines#DuplicateFiles