Created attachment 1112423 [details]
logs

Description of problem:
Retype a volume without using "--migration-policy" optional argument is failed  with "Could not find a host for volume...", however when using this optional argument the operation succeed 
Another issue is that there is not an indication to the failure from CLI 

* I used 2 Netapp-nfs as back ends 

Version-Release number of selected component (if applicable):
openstack-cinder-2014.2.3-11.el7ost.noarch
python-cinder-2014.2.3-11.el7ost.noarch
python-cinderclient-1.1.1-1.el7ost.noarch

How reproducible:
100%

Steps to Reproduce:
1. Retype a volume to a new back end without using the optional argument: "--migration-policy"

Actual results:
Retype a volume is failed with "Could not find a host for volume..."
There is not an indication to the failure from CLI  

Expected results:
The migration should also succeed, while not using "--migration-policy" optional argument
If the migration has failed should be an indication to the failure from CLI