Description of problem:
The "Network Label" field in "New Logical Network" (add network) under "create on external provider" should be mandatory.
If this field is empty the error in the UI is:
Error while executing action AddNetworkOnProvider: Failed to communicate with the external provider.


And the error from the neutron server is:
2013-08-11 17:08:02    ERROR [quantum.api.v2.resource] create failed
Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/quantum/api/v2/resource.py", line 82, in resource
    result = method(request=request, **args)
  File "/usr/lib/python2.6/site-packages/quantum/api/v2/base.py", line 369, in create
    obj = obj_creator(request.context, **kwargs)
  File "/usr/lib/python2.6/site-packages/quantum/plugins/linuxbridge/lb_quantum_plugin.py", line 408, in create_network
    physical_network, vlan_id = db.reserve_network(session)
  File "/usr/lib/python2.6/site-packages/quantum/plugins/linuxbridge/db/l2network_db_v2.py", line 117, in reserve_network
    raise q_exc.NoNetworkAvailable()
NoNetworkAvailable: Unable to create the network. No tenant network is available for allocation.


From engine log:
2013-08-11 17:15:17,120 ERROR [org.ovirt.engine.core.bll.provider.network.AddNetworkOnProviderCommand] (ajp-/127.0.0.1:8702-2) Command org.ovirt.engine.core.bll.provider.network.AddNetworkOnProviderCommand throw Vdc Bll exception. With error message VdcBLLException: (Failed with error PROVIDER_FAILURE and code 5050)
2013-08-11 17:15:17,124 INFO  [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (ajp-/127.0.0.1:8702-2) Correlation ID: 1014ffb3, Call Stack: null, Custom Event ID: -1, Message: Failed to add Network neutrom_net1 to Data Center: Neutron_DC


Version-Release number of selected component (if applicable):
rhevm-3.3.0-0.14.master.el6ev.noarch
openstack-quantum-2013.1.2-4.el6ost.noarch


Steps to Reproduce:
1. Add new network and select "create on external provider"
2. Leave "Network Label" field empty