build: sync glusterfs.spec.in with Fedora glusterfs.spec

(This is the release-3.4 branch.)

 * remove G4S/UFO from community packaging. The Fedora/EPEL packaging
   will follow suit once the glusterfs-openstack-swift packaging
   materializes from the G4S team. Note that for the time being 'make dist'
   still creates a UFO tarball from the .../ufo directory for use by
   fedora packaging.
 * add glusterfs-api and glusterfs-api-devel sub-packages
 * add extras/systemd/glusterd.service. Use it (or extras/init.d/glusterd)
   instead of the Fedora versions.
 * restores ability to build glusterfs RPMs from the dist tarball with
   'rpmbuild {-ts,-tb,-ta} glusterfs-XXX.tar.gz'
 * reverse {--with,--without}_fusermount in sync with fedora .spec and
   master branch
 * other minor cleanups mostly to sync with fedora .spec and to build
   from the dist tarball. Any differences will be resolved in the fedora
   .spec in the next release (i.e. beta4 or GA).
 * this is nominally for "the impending merge of .../api from master" but
   should be independent of that change.

(still deciding whether to add the fedora glusterfsd.{init,service) files
here or remove them from fedora.)

BUG: 819130
Change-Id: I90c7355ca02239995b1df7646e3cd10ec227bcc5
Signed-off-by: Kaleb S. KEITHLEY <kkeithle@redhat.com>
Reviewed-on: http://review.gluster.org/5179
Reviewed-by: Niels de Vos <ndevos@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>