Fixed location pref tests for iOS7 iOS8

@jlipps can you check if this fixes the test for you. There was instability cause by failed xcrun erase leaving the Simulator folder in a bad state. 

@Jonahss could you check the xcrun erase part, 500ms was not enough.


ok, if it doesn't affect the validity of the test, can you add a comment like "not important, just sleep a bit so we can visually see what's going on with the test"

or you could just have it when you are testing if it really doesn't matter.