vm should return false if power action returns bad_request

Also logging error with fog_logger
Corrected edge_gateway schema and removed bad test

Fixes after running tests against clean and new org
Merge pull request #2245 from alphagov/error_handling_for_vms

[vcloud_director] vm should return false if power action returns bad_request
Merge pull request #2246 from alphagov/vcloud_director_edge_gateway_test_fixes

[vcloud_director] Corrected edge_gateway schema and removed bad test