Update logfile ownership for syslog in Ubuntu

With $FileGroup:$FileOwner = root:adm, we would have some
syslog logfiles inaccessible then syslog running user would
be changed from root to syslog.
root:adm should not be set for syslog logfiles since
we use syslog:syslog as drop-provilege-to as well
(http://www.rsyslog.com/doc/droppriv.html)

Closes-bug: #1308684

Change-Id: I4ab98cd77d29d986d202051b7e66c8abb13e4c15
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
Merge "Update logfile ownership for syslog in Ubuntu"