pre-start: touch/configure vdsm logs

During pre-start of vdsm we must create vdsm logs files
with proper perms/user/group/ if they doesn't exist.
This situation happens currently because during
ovirt node build it cleans /var/log dir so it will
remove all vdsm logs created during rpm install.

Change-Id: I6ca927cb447eeb24195cff6a1174e0f9a7295214
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/25912
Reviewed-by: Dan Kenigsberg <danken@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/26095