Added init scripts for
- SysvInit(CentOS 6 or Red Hat 6)
- rc.d (FreeBSD)

Most of the latest distributions are using systemd. Support to be
added for other distributions which are not using systemd.

Removed systemctl wrapper functions(start/stop/status) from
gluster-eventsapi CLI(peer_eventsapi.py). Status and Reload
re-implemented using pid file check.

Added pid file support for glustereventsd.

Following dependencies removed
python-flask - Only used for example dashboard. User can install
if required.
python-fasteners - Not available for EPEL 6, added custom code using
fcntl as replacement.

> Reviewed-on: http://review.gluster.org/15367
> Smoke: Gluster Build System <jenkins@build.gluster.org>
> CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
> Reviewed-by: Niels de Vos <ndevos@redhat.com>
> NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
> Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>

BUG: 1374649
Change-Id: I26792eae9b11e93304f70b3997cd7d8d03b067f4
Signed-off-by: Aravinda VK <avishwan@redhat.com>
(cherry picked from commit 5a1abd235d05809bc7a5c4b94ae7bb51add6fc9c)
Reviewed-on: http://review.gluster.org/15453
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
Smoke: Gluster Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Atin Mukherjee <amukherj@redhat.com>