Fix failure of OvsdbTestGetBridgeDomainsIT

OvsdbTestGetBridgeDomainsIT was failing due to a NullPointer to the
ConfigurationService.invetoryServiceInternal

- Add InvetoryService to TestObjects
- Call setInventoryServiceInternal on the ConfigurationService

Change-Id: I1ec373df3b2726aca613ee740b4768bc9d28954e
Signed-off-by: Dave Tucker <dave@dtucker.co.uk>