ceph.spec.in, init-ceph.in: Don't autostart ceph service on Fedora.

This patch is taken from the current Fedora package and makes the upstream
ceph.spec compliant with Fedora policy. The goal is to be fully compliant
upstream so that we can replace current Fedora package with upstream
package to fix many bugs in Fedora.

Addition from Dan Mick <dan.mick@inktank.com>:
Do this for RHEL and Centos as well, since they surely will benefit
from the same policy.

Signed-off-by: Erik Logtenberg <erik@logtenberg.eu>
Signed-off-by: Dan Mick <dan.mick@inktank.com>:
ceph.spec.in: We need those nice recent changes for rhel7 in Fedora too.

Signed-off-by: Erik Logtenberg <erik@logtenberg.eu>
ceph.spec.in: Obselete ceph-libcephfs (not libcephfs)

I am guessing that because it was a sub-package libcephfs was mistakenly
used instead of ceph-libcephfs.

Signed-off-by: Sandon Van Ness <sandon@inktank.com>
ceph.spec.in: No version on ceph-libs Obsoletes.

If we are installing with the new package structure we don't ever want the
new package to co-exist with the old one; this includes the mistakenly-
released v0.81 on Fedora, which should be removed in favor of this
version.

Signed-off-by: Sandon Van Ness <sandon@inktank.com>
Reviewed-by: Dan Mick <dan.mick@inktank.com>
ceph.spec.in: Obsolete all older versions.

Now this changeset can be used on all current ceph releases that already
have the package split.

Signed-off-by: Erik Logtenberg <erik@logtenberg.eu>
ceph.spec.in: Add a small comment on the empty %files section

as suggested by Dan Mick.

Signed-off-by: Erik Logtenberg <erik@logtenberg.eu>