virtmanager: add selinux domain

Address any denials in the log - currently just adding
the virtualization service.

Bug: 183583115
Test: ps -AZ | grep virtmanager
u: r:virtmanager:s0             virtmanager   2453     1 10930880  4544 0                   0 S virtmanager
Change-Id: Ie034dcc3b1dbee610c591220358065b8508d81cf
5 files changed