Fixed missing Requires: freetype2 for Fedora

This reverts https://github.com/OpenRA/OpenRA/pull/4305. While this works on proper build bot VMs at https://build.opensuse.org/package/view_file/games/openra/openra.spec?expand=1 the 0%{?fedora} or 0%{?suse} RPM macros will always be zero on our Ubuntu build server which also feature a very old and hacked version of rpmbuild. I should have known that this will be a problem. Sorry.