Couple of fixes for running in a chroot or as root

I was trying to fix the colord tests in a chroot, as in Ubuntu we run them as automatic regression tests and they weren't passing.

 - In a chroot we might not have a seat, so don't require this.
 - polkit auth doesn't work in this environment, so I tried running as root. It then turns out that the device path doesn't include the uid or username, so fall back to trying this.

Also while running as root, I get the /colord/client{import} test failing with this message

/colord/client{import}: **
libcolord:ERROR:cd-test-daemon.c:1519:colord_client_import_func: assertion failed (error == NULL): The profile was not added in time (cd_client_error, 0)

haven't been able to figure out how to fix this one (it works in a real system).