Cleaned up tests to be closer to other facades
Make the Azure provider compatible with the most recent version of gwacl.
[r=dimitern] state/api/machiner: Cleanup tests and code

This is a trivial change in the machiner API
facade's implementation and test suite to make
them closer to the other facades.

Next in line is replacing state calls with API
calls in the machiner worker.

https://codereview.appspot.com/11463044/
testing/checkers: fix Satisfies
[r=rvb] Azure provider: support most recent gwacl
testing/checkers: explicit values in test table
[r=rogpeppe] testing/checkers: fix Satisfies

It didn't work when called with a nil argument.
A reflect gotcha to remember.

https://codereview.appspot.com/11560044/