test_setup: Wait for polkit to take effect

After some research, we found that polkit rule will take 1 second to
take effct after change. This will cause some fail cases if interval
between checking access and writing rule are short enough.

We found wait 1 second is enough to avoid any occurance of this fail.
Of course this will add about 5min(~300s) to the whole test run. But
I think it's worth to avoid unexpect fail run.

Signed-off-by: Hao Liu <hliu@redhat.com>