Part of this test uses `qemu-nbd -k SOCKPATH`, and passes
that socket to libvirt. SOCKPATH will have label user_home_t,
which svirt_t can't access, so running with selinux enforcing this
test will always fail.
Manually change the socket label to svirt_image_t which makes
selinux happy.
Note: libvirt does not relabel most (all?) externally managed socket
paths. I think this is correct, since in theory this could be a
socket shared with other processes, so its up to the user to ensure
DAC/MAC permissions are acceptable for their usecase.
Signed-off-by: Cole Robinson <crobinso@redhat.com>