build/pkgs/gap: add more fedora package information

The GAP subpackages listed at,

  https://packages.fedoraproject.org/pkgs/gap/

are not included with the superpackage install, so we have to list
the ones that we use explicitly.

Author: orlitzky

build/pkgs/gap/distros/fedora.txt

@@ -1 +1,5 @@
 gap
+gap-core
+gap-devel
+gap-libs
+libgap