Replace makeStubMethod with sinon.stub in the changes utils tests.
Replace makeStubMethod with sinon.stub in the changes utils tests.

mitechie/juju-gui,bac/juju-gui,mitechie/juju-gui,bac/juju-gui,bac/juju-gui,mitechie/juju-gui,mitechie/juju-gui,bac/juju-gui