Make role `ceph-mgr` handling itself the installation of `ceph-mgr`
package because it's complicated to manage it regarding we are going to
install `jewel vs. luminous`
Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>
`ceph_release` isn't available at this step of the playbook because it
is set later based on the installed binaries.
Closes: https://bugzilla.redhat.com/show_bug.cgi?id=1486062
Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>