ceph.spec.in: package rbd-replay-prep on all Fedoras

ceph.spec.in: package rbd-replay-prep on all Fedoras

This reverts the change in commit
85517d611b7bf4cb6cbffcd2c65303be0d038264. Since we BuildRequire:
libbabeltrace-devel, autoconf will see that babeltrace is available
during the build, and make will build/install the rbd-replay-prep
utility.

This change also simplifies Fedora selection logic, because Fedora 19 is
EOL, so "%{fedora}" implies "Fedora 20 and above".

Reported-by: Ira Cooper <ira@samba.org>
Signed-off-by: Ken Dreyer <kdreyer@redhat.com>
(cherry picked from commit 2db9480fa2646de776f0076d82747e202e574ddd)