Fix tests where schema version is not supported

Tests were failing on earlier ovs versions because the schema version did not support certain tables. In these cases a bridge was created and not deleted because only part of the test ran.

Add assumeTrue() around the schema version check to all tests with a problem schema version to allow the test to continue.

Change-Id: I752c52ed483c252a4564fd24d6353654fc209a33
Signed-off-by: Sam Hague <shague@redhat.com>