Add SecurityGroup revoke test and lib

Change-Id: I1c955d6482054c6431c9ab34efd72cc9299a40d3
Add pub and priv ip ping test to BasicInstanceChecks

Change-Id: I902ee3fa98386a9f8071616ed2d8288919a261d7
Split up cidr and sg auth tests

Change-Id: Iea4ce7d43c546d41e97c1bdc0a6c91f2fdaebd04
Fix get_emi defaults

Change-Id: I4d7616141ff9b2a3fccd0e4d9fa00cccacf35791