Description of problem:
In our CI those tests failed .
We run our CI with default network quotas parameters (10) as a result  when all tests run it fails when system reach to 10 networks.

neutron.tests.tempest.api.test_revisions.TestRevisions.test_update_router_bumps_revision
neutron.tests.tempest.api.test_revisions.TestRevisions.test_update_router_extra_routes_bumps_revision
neutron.tests.tempest.api.test_revisions.TestRevisions.test_update_subnet_bumps_network_revision
neutron.tests.tempest.api.test_revisions.TestRevisions.test_update_subnet_bumps_revision
neutron.tests.tempest.api.test_revisions.TestRevisions.test_update_subnet_service_types_bumps_revisions

Version-Release number of selected component (if applicable):
openstack-tempest-15.0.0-1.el7ost.noarch
puppet-tempest-10.3.0-0.20170210202111.47a23ee.el7ost.noarch
python-tempest-15.0.0-1.el7ost.noarch
python-tempestconf-1.0.1-0.20170307153443.0890319.el7ost.noarch

How reproducible:
always 

Steps to Reproduce:
1.run tempest : neutron.tests.tempest.api.test_revisions.TestRevisions*
2.
3.

Actual results:
 Failed 7 times in the last 7 runs. Stability: 0 %
Stacktrace

Traceback (most recent call last):
testtools.testresult.real._StringException: Empty attachments:
  stderr
  stdout

pythonlogging:'': {{{
2017-03-19 05:03:56,640 32150 INFO     [tempest.lib.common.rest_client] Request (TestRevisions:test_update_subnet_bumps_network_revision): 409 POST http://10.0.0.102:9696/v2.0/networks 0.032s
2017-03-19 05:03:56,641 32150 DEBUG    [tempest.lib.common.rest_client] Request - Headers: {'Content-Type': 'application/json', 'Accept': 'application/json', 'X-Auth-Token': '<omitted>'}
        Body: {"network": {"name": "test-network--896537325"}}
    Response - Headers: {'status': '409', u'content-length': '110', 'content-location': 'http://10.0.0.102:9696/v2.0/networks', u'date': 'Sun, 19 Mar 2017 09:03:57 GMT', u'content-type': 'application/json', u'connection': 'close', u'x-openstack-request-id': 'req-b4cb52e3-57e1-46c8-8648-a1abf053ca94'}
        Body: {"NeutronError": {"message": "Quota exceeded for resources: ['network'].", "type": "OverQuota", "detail": ""}}
}}}

Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/neutron/tests/tempest/api/test_revisions.py", line 66, in test_update_subnet_bumps_network_revision
    net = self.create_network()
  File "/usr/lib/python2.7/site-packages/neutron/tests/tempest/api/base.py", line 220, in create_network
    body = cls.client.create_network(name=network_name, **kwargs)
  File "/usr/lib/python2.7/site-packages/neutron/tests/tempest/services/network/json/network_client.py", line 142, in _create
    resp, body = self.post(uri, post_data)
  File "/usr/lib/python2.7/site-packages/tempest/lib/common/rest_client.py", line 276, in post
    return self.request('POST', url, extra_headers, headers, body, chunked)
  File "/usr/lib/python2.7/site-packages/tempest/lib/common/rest_client.py", line 665, in request
    self._error_checker(resp, resp_body)
  File "/usr/lib/python2.7/site-packages/tempest/lib/common/rest_client.py", line 777, in _error_checker
    raise exceptions.Conflict(resp_body, resp=resp)
tempest.lib.exceptions.Conflict: An object with that identifier already exists
Details: {u'message': u"Quota exceeded for resources: ['network'].", u'type': u'OverQuota', u'detail': u''}


Expected results:


Additional info: