Removing bad Failure test

@krames I removed this test because it fails after the changes in b359376da042858fb6543df68f47679f09bd8e5c

Specifically the fog/lib/fog/rackspace/requests/monitoring/list_entities.rb file.  The changes that took place in the commit appear totally correct.  The question I have to ask now is, how would we go about writing a failing test for this case?  I struggle to find a test that is useful for this.  

I noticed that the commit deleted the failure list_overview test and did not replace it, so perhaps there isn't a good test that can be written for these requests?