Move multipath configuration to vdsm-tool configurator

Previously multipath is reconfigured on each vdsm
service restart.

multipath.conf should not be changed since important changes
done by the sysadmin are needed and might be overwritten.

vdsm will fail to start if multipath configuration is
required.

Multipath will be reconfigured only on user demand
using "vdsm-tool configure --module multipath".

as part of the move to using vdsm tool configurator for multipath,
we want to consolidate the configuration of multipath with
other configurators, such as libvirt.
Rotating the configuration file will end up deleting the
original multipath conf file for the user,
- pre vdsm installation. So we'll use backup files with
timestamp instead of rotation.

Change-Id: Ife045908dc6e2aea9829b51482b909af1faf79da
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1076531
Signed-off-by: Yeela Kaplan <ykaplan@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/30909
Reviewed-by: Dan Kenigsberg <danken@redhat.com>