Wavefunction API updated now in fake_QVM for test

fake_qvm constructed for testing now returns a tuple when wavefunction is
called.

grove/pyvqe/tests/test_algorithms.py

@@ -73,7 +73,7 @@ def rotation_wavefunction(phi):
     minimizer.return_value = fake_result
 
     fake_qvm = Mock(spec=['wavefunction', 'expectation', 'run'])
-    fake_qvm.wavefunction.return_value = rotation_wavefunction(-2.5)
+    fake_qvm.wavefunction.return_value = (rotation_wavefunction(-2.5), [0])
     fake_qvm.expectation.return_value = [0.28366219]
     # for testing expectation
     fake_qvm.run.return_value = [[0], [0]]