redis system.py paths need update for rhel/centos/fedora

[Pete MacKinnon]

Some of the paths currently defined in the "redhat" stanza of the redis guestagent datastore code don't match the redis packages currently available for Fedora/CentOS/RHEL:

REDIS_CONFIG = '/etc/redis/redis.conf'
REDIS_BIN = '/usr/libexec/redis-server'

Also, systemctl is prefrerred for service enablement/start/stop.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/171323

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/171323
Committed: https://git.openstack.org/cgit/openstack/trove/commit/?id=d50ec86c64b0df91bd96ebb3d93c1c457945c9b1
Submitter: Jenkins
Branch: master

commit d50ec86c64b0df91bd96ebb3d93c1c457945c9b1
Author: Peter MacKinnon <email address hidden>
Date: Tue Apr 7 14:34:28 2015 -0400

    Update redis system.py paths for current RHEL/CentOS/Fedora

    Some of the paths currently defined in the "redhat" stanza
    of the redis guestagent datastore code don't match the
    redis packages currently available for Fedora/CentOS/RHEL.

    Change-Id: I09fb5e426db57ed76ff23ee6c230229039a3897d
    Closes-Bug: #1440785