should not test the default accessibility plist contents

these were bad tests because the contents of the plist were subject to
change (by Apple), were not stable from run to run, and were not
germane to the topic at hand: testing if we could enable accessibility.
Merge pull request #369 from calabash/feature/accessibility-spec-should-not-test-default-accesibility-plist

should not test the default accessibility plist contents