Currently in IBM storwize_SVC driver, user can specify only one IO
group per backend definition. The user now may specify a
list of IO groups, and at the time of creating the volume, the driver
will select an IO group which has least number of volumes associated
with it. The change is backward compatible.
Please see blueprint for full details.
Implements: blueprint ibmsvciogrpselection
DocImpact
Change-Id: I4766fc03bdacdde5dd9cfd4899c6cc5c2aee0d00
d0c9a052fb