Bug 1026424 - Remove frame switching in gallery app tests where possible

Here we could also do: 
<code>self.wait_for_condition(lambda m: self.apps.displayed_app.name != 'Gallery')</code>
or
<code>self.wait_for_condition(lambda m: self.apps.displayed_app.name == 'Contacts')</code>
I'm fine with whatever you choose, the test is passing either way.