Switched around hwsim rules with the IWD initializer to avoid
IWD periodically scanning before hwsim rules are in place. Removed
some unneeded code during teardown.
Running autotests with native hardware will not work on tests which
depend on the hwsim python API (since hwsim will not be running).
For these tests, it will now be required that they specify:
needs_hwsim=1
This allows the test to be skipped when running with native hardware
rather than the test failing with a python exception.
