This is causing the browser to hang for me when running `test_that_pinning_filter_persists_for_session`. I'm not sure why, but the browser just hangs, and when I kill it and look through the trace [1], I can see that this is the last line of code from moztrap-tests that has been executed.

Can anyone else confirm or deny this behaviour?

[1] http://pastebin.mozilla.org/2839732