The removal of AlreadyAtatchedClient exception from neutronclient
suddenly causes the failure of neutronclient icehouse job.
It is better to wait the removal of the exception until Icehouse EOL
(which will come soon).

This reverts commit 30b198edec988d7c969c1edd4a2754bd9c9c79f4.
Closes-Bug: #1441969

Change-Id: Ifa02a4ca39bc9c0fe9b65d5b0d66c588885cb12c

This exception is no longer referenced in Horizon.  It should
be removed as noted in the TODO being removed.

Change-Id: I9970ca375d19476c12891475d0a8c0c559e0507f

* all modules are using function of _ from oslo.i18n
* remove the definition of _ from openstack.common.__init__.py for safety

Change-Id: Ice2f8be1190fd13e8991a8c7fa55ca636341e875
Closes-Bug: #1382476

When posting an 'attach interface' request to Nova with an invalid
ip for defined network, Nova returns an HTTP 500 error. In fact,
Neutron returns 'InvalidInput' error, but Neutron client is not able
to translate this error to a specific exception. So that a general
'BadRequest' exception is thrown. Neutron client and Nova need a more
specific Neutron error type, in order to address and translate the
error in to a proper Nova exception.

Change-Id: Idd964c33476d7559f642287d577f8a6122d7674c
Partial-Bug: 1369871

Change-Id: If6cf2caeae294db30a8988ab861441211b651580

Nova needs a specific client exception defined for the server's
MacAddressInUse exception when allocating ports so it can handle the
exception properly, otherwise the NeutronClientException with a 409 can
be confused with other errors.

Partial-Bug: #1347778

Change-Id: Ia02dbc8fe32a43adeb229e3b640b9b33ec0dd6c7

nova contains plenty of code like:
  except neutron_client_exc.NeutronClientException as e:
      if e.status_code == 409:
          ...

This change declares a fallback of 0 for exceptions without a more
explicit status code.  This was the behaviour prior to Change-Id
I99b9560b3afaf5884fd00353323267da450338fa

Change-Id: Ib736205066fd5cd9738fd3fb3b64f6590803cf39

In nova, there is no way to explictly knows whether the neutron
fails due to over quota or no more floating ips and fixed ips.
so nova need to check whether the return value is 409 in order to
raise an over quota exception. It's easier in neutronclient to
raise the exception then nova will handle it.

Related-Bug: #1210598

Change-Id: I8788993578ac872da9f676fe3e2fb8f98414289d

- Map exceptions from neutron server into corresponding client
  exceptions automatically (without exception mapping dict).
  An exception from Neutron server 'SomeException' will be
  mapped to an exception 'SomeExceptionClient' ('Client' suffix)
  if it is defined.

- If no corresponding exception is defined in client side,
  an exception per response code will be used. Previously
  NeutronClientException was used for all cases and a user
  of client library cannot know exception type without
  checking exception.status_code. It allows client lib users
  (such as Horizon) to handle exceptions more easily.

- All exceptions from client libarry inherit NeutronClientException
  and all CLI related exceptions inherits NeutronCLIError now.

- Remove unused exceptions (including Quantum v1 related)
- MalformedRequestBody is renamed to MalformedResponseBody
  because it is raised in deserializer and deserializer is
  used to parse not request but response.

Closes-Bug: #1296148
Change-Id: I99b9560b3afaf5884fd00353323267da450338fa