tempest rest_client _error_checker fails while parsing response

[Evgeny Fedoruk]

Running tempest test on devstack (happens also on jenkins gate)
    nosetests -sv tempest.api.network.test_load_balancer.py

create_vip failes and returns:
<?xml version='1.0' encoding='UTF-8'?>
<NeutronError xmlns="http://openstack.org/quantum/api/v2.0" xmlns:quantum="http://openstack.org/quantum/api/v2.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">Request Failed: internal server error while processing your request.</NeutronError>

tempest/common/rest_client.py:RestClient._error_checker (line 484: message = resp_body['error']['message']) fails.

....
  File "/home/radware/tempest/tempest/common/rest_client.py", line 448, in _error_checker
    message = resp_body['error']['message']
TypeError: string indices must be integers, not str

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/76475

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/76475
Committed: https://git.openstack.org/cgit/openstack/tempest/commit/?id=6cb6d190f4eb45ad9958be5e4a80e727e850304f
Submitter: Jenkins
Branch: master

commit 6cb6d190f4eb45ad9958be5e4a80e727e850304f
Author: vponomaryov <email address hidden>
Date: Fri Mar 7 09:39:05 2014 +0200

    Fixed _error_checker in rest client

    Restclient's method '_error_checker' for response codes 500 and 501 gets key
    error exception when 'resp_body' is a string and passes conditions for
    containing of keys.
    Also added fix to rarely raised Exceptions after separation main and base
    exceptions for two modules.

    Closes-Bug: #1280767
    Closes-Bug: #1289190
    Partially-implements: bp unit-tests
    Change-Id: I4b909d008940f8a96efc922daac64a086819c78a