Check if bridge exists and make sure it's UP in ensure_bridge

Introduce _bridge_exists_and_ensure_up that checks if the bridge
exists and if it's DOWN sets it UP

Change-Id: Ide9d2bb04016cadb347b00cadbee7007e61bd01e
Closes-bug: #1282741
NSX: Fix fake_api_client to raise NotFound

If one quries NSX doing GET /ws.v1/lswitch/LS_UUID/lport and LS_UUID
is a UUID that does not exist in NSX. NSX raises a 404. If LS_UUID is *
NSX returns an empty result string. This patch fixes the fake_api_client
so that it's behavior is correct.

Change-Id: Id66299d6ae3cfa43a65d4cb28f34348d64d8ed65
Closes-bug: 1311291
Imported Translations from Transifex

Change-Id: I35cb53cb3a7a5c151c20be1d6ab7b7447e5c22d1
Merge "NSX: Fix fake_api_client to raise NotFound"
Merge "Imported Translations from Transifex"
Merge "Check if bridge exists and make sure it's UP in ensure_bridge"