security: Move Selinux stuff into function

Selinux relabeling is moved into a function to prevent circular imports.

Change-Id: I98690e612a3e299ec2a8b4641a214062f2dea059
Signed-off-by: Fabian Deutsch <fabiand@fedoraproject.org>
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>