Factor out setting of allowed devices so that we can update allowed devi...

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Co-Authored-By: Ian Main <imain@redhat.com>
Docker-DCO-1.1-Signed-off-by: Chris Alfonso <calfonso@redhat.com> (github: calfonso)
I know that this isn't related to the refactoring out, but it erks me that this comment is wrong ;).  There shouldn't be two bullet points here.  We need wild cards period.  It's not limited to `/dev/pts` support.  We need wild cards so that we can um, use wild cards to allow/deny *any* device class that might want to be allowed/denied.