Convert keypair tests to httpretty

Change-Id: I6876d97dd6600a0a34b89d9f693078f495085622
blueprint: httpretty-testing
Convert limit tests to httpretty

Change-Id: I10e0357e0f79c009a00759fd22e6148d10b5286d
blueprint: httpretty-testing
Merge "Convert keypair tests to httpretty"
Merge "Convert limit tests to httpretty"