drop --cluster from ceph-disk activate (osd).

This commit removes the --cluster option from the 'ceph-disk activate'
part of the osd configuration (when the cluster is given as an arg).
Only 'ceph-disk prepare' accepts a cluster option.

Change-Id: I4027690c36141a184c1fb1b64b382e17cbbcf487
Closes-Bug: #1323120
Support for RedHat in ceph::mon

Support for RedHat in ceph::mon and in ceph::mon, ceph::keys CI tests.

Yumrepo isn't propperly removed but only disabled. This leads to a need
to ensure => absent on the ceph::repo whenever a switch to a different
ceph version happens. Therefore it's refactored run tests ordered by
release

Change-Id: I51150c1e3316bdab20c4458e79c4aeeb15fe4bd2
Closes-Bug: #1264916
Closes-Bug: #1323841
Fixed removal command in ceph::osd

And updated the CI tests. ceph::repo needs to be removed whenever
a different release is targeted. This is mainly because "enabled" is
used in yumrepos, because of the lack of "ensure" in Puppet < 3.5
Refactored to not have to switch ceph::repo constantly, but run tests
on a per release order.

Change-Id: I555acda7413765aaa99f922893649e1f13215450
Closes-Bug: #1264916
Closes-Bug: #1323841
Closes-Bug: #1323838
Merge "drop --cluster from ceph-disk activate (osd)."
Remove unnecessary if statement in ceph::mon

A previous patchset implementing RedHat family support for ceph::mon had
an erroneous if statement in the OS selection code.
This is fixed here, in its own patchset though, as changes to the previous
patchset failed the CI tests (and even crashed the test infrastructure as
it got stuck indefinitely.)

The removal of the if statement requires some changes in the tests as well.

Also added a check for the exec in RedHat family.

Change-Id: I38fbf189c806a21c40bb55dd47d6debb3a592b89
Merge "Support for RedHat in ceph::mon"
Merge "Fixed removal command in ceph::osd"
Merge "Remove unnecessary if statement in ceph::mon"