Python 3: fix test_ovs_tunnel

Python 3: fix test_ovs_tunnel

In Python 3, this happens:

>>> d = {}
>>> a = d.values()
>>> b = d.values()
>>> a == b
False

And anyway we're not really willing to pass dict_values objects around; we are
expecting lists, just like in Python 2, so let's just do the conversion.

Change-Id: I62ef32d50ba5ce64a653ffc62ba18c53cab9b15c
Blueprint: neutron-python3