Fix NeutronIT testGetTunnelEndpoint

The test was broken in that it attempted to update all fields of the OpenVSwitch
row. That is not valid due to immutable columns, such as _version.

Change-Id: I214e96914d85a0ca8321bf7c3e498f9a46f24f0e
Signed-off-by: Flavio Fernandes <ffernand@redhat.com>
(cherry picked from commit d8a87991438e3a4b790f773b46e4e88011f922ff)