vdsmd.init: do not use previous libvirt logrotate

In the past VDSM have been creating /var/log/libvirtd.log to track libvirt
calls and also add rule for such file into /etc/logrotate.d/libvirtd.
However, now VDSM uses /var/log/libvirt/libvirtd.log (commit fe01963f)
and should replace any previous conf on /etc/logrotate.d/libvirtd
with VDSM suggestions.

Change-Id: Iaa9707d892bb03a029300f62ae1ed204cea52486
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/16528
Reviewed-by: Sandro Bonazzola <sbonazzo@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>