Remove RHEL6 specific code in prescript.pp

Because there are no more EPEL6 repositories on
https://repos.fedorapeople.org/repos/openstack/openstack-juno/
this code can be removed.

Change-Id: I2b212ac1121f27dbc943c86610d14b6bbb52d7b3
Configure TCP keepalive setting to all nodes

In some cases, it has been observed that services keep their
connection to RabbitMQ when they should not (e.g. during a
controller server hard reboot), creating instability. This patch
aims at fixing this by setting TCP keepalive parameters for
RabbitMQ connections, and setting kernel parameters to send
keepalive packets more often.

Change-Id: I7688a86e4ff617f20d6767f156c5d880e0d4d619
Fixes: bz#1167414
Packstack Plugins Clean-up

- Deleted unused import
- Pep8 compliance
- Deleted unused variables

Change-Id: I45f135b2467427cd7ee3b5ba32745af2a631458a
Signed-off-by: Gael Chamoulaud <gchamoul@redhat.com>
redis-based group membership coordination for ceilometer

If CONFIG_CEILOMETER_COORDINATION_BACKEND is set to 'redis'
then a redis manifest is created to install redis on the
appropriate host and configure the ceilometer-central-agent
and ceilometer-alarm-evaluator to use it for group membership
coordination.

Change-Id: I07261f5fd433c13a57a614c15b13f0cad6c79d6a