Comment 0 for bug 1586593

With "transfer-accept" user can accept a volume which is larger than quota "per_volume_gigabytes".

Reproduce steps:
1. update tenant demo's per_volume_gigabytes to 1.
    $ cinder quota-update --per-volume-gigabytes 1 bac0caa2d69947b78fc3c77b156e13a5

2. create a 2 gb volume in tenant admin, and create a transfer from the volume.
    $ export OS_TENANT_NAME=admin
    $ export OS_USERNAME=admin
    $ cinder create 2
    $ cinder transfer-create bf913e66-5cfe-43e7-8721-59d94882ba7a

3. use tenant demo to accept the volume
    $ export OS_TENANT_NAME=admin
    $ export OS_USERNAME=admin
    $ cinder transfer-accept 47561a3c-a4e8-44ca-9b6f-41372470c933 e9b7fc648da8b6f8

Now demo get a volume in size 2G, even if it's per_volume_gigabytes is 1G.