Fix solidfire accept_transfer

Previous fix has a mistake which makes the situation worse.  This change
fix volume['project_id'] and volume['user_id'] and adds unit test for
accept_transfer.

Closes-bug: # 1349475

Change-Id: I7b2bcefa4c8d173689cc63ee5aa9e00397c7f8ca
Merge "Fix solidfire accept_transfer"