Add to logrotate conf file that new created logs will be owned by vdsm

Using create options that set each new log file to mode 644 owned by
user vdsm and vdsm group

Bug-Id: https://bugzilla.redhat.com/show_bug.cgi?id=912308
Change-Id: I67ab9159cd482c2fc405ee0a316c46a976799af8
Signed-off-by: Yaniv Bronhaim <ybronhei@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/12160
Reviewed-by: Dan Kenigsberg <danken@redhat.com>