Stop ignoring 400 errors returned by ODL

This commit stops ignoring 400 (Bad Request) HTTP codes returned by ODL
in create and update operations. It also modifies sendjson() because it
doesn't ignore any HTTP error code now.

Change-Id: Id0db2c0c1d8fddfbd16b3ce9476a2358e2ef1e49
Closes-Bug: #1369239
ML2 Cisco Nexus MD - not overwriting existing config

The Cisco Nexus ML2 MD overwrites any existing switchport
VLAN config such as management VLANs that are preconfigured
in the compute node ToR interfaces.
This bug addresses that issue and ensures the config is not
wiped out.

Closes-Bug: 1330597

Change-Id: Ie2969e5750a179a4940d12db4c9ee6e1ec53b79b
Use stop() method on MessageHandlingServer

MessageHandlingServer has no kill() method. In case neutron server using
rpc workers and is stopped, wrong method is called.

Change-Id: Id4a11f3dca070e684fb9e079139ac09792bc7aad
Closes-Bug: 1387053
Merge "ML2 Cisco Nexus MD - not overwriting existing config"
Imported Translations from Transifex

For more information about this automatic import see:
https://wiki.openstack.org/wiki/Translations/Infrastructure

Change-Id: Icd40b3f0556c735637c940072306c52124df2f54
Merge "Use stop() method on MessageHandlingServer"
Merge "Stop ignoring 400 errors returned by ODL"