The DAC driver ignores the relabel='no' attribute in chardev config

  <serial type='file'>
    <source path='/tmp/jim/test.file'>
      <seclabel model='dac' relabel='no'/>
    </source>
    <target port='0'/>
  </serial>

This patch avoids labeling chardevs when relabel='no' is specified.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Signed-off-by: NJim Fehlig <jfehlig@suse.com>