Delete volume transfer in volume_destroy function

Doing volume force delete operation on volume-A will change volume-A's
status to 'deleted', so all related data about volume-A should be deleted.
Now current version's volume_destroy function doesn't delete related data
of volume transfer. If there is volume transfer about volume-A, first do
force delete operation on volume A, and thus the volume-A's transfer data
would be residual. So remove the related data of volume transfer in
volume_destroy function.

Change-Id: Id80a6e0cc061fccb02af60706244be043abdd72d
Closes-Bug: #1270785
(cherry picked from commit 19d8040d61d453ec3916d74c628189ca0b54ac59)
Raise max header size to accommodate large tokens

The max header is exceeded in the following scenario
- Auth tokens built with a keystone v3 API catalog
- A catalog with approximately 8 or more endpoints defined

An equivalent fix will be required for all projects which use
eventlet.wsgi.

Copied from https://review.openstack.org/#/c/33362/

Closes-Bug: 1190149

Change-Id: I3fcb196b25a7a477b799c8dfa2ff5115977ca06d
(cherry picked from commit aa1ba1f0176af286506e4188628e5acbb8f7f0e6)
Merge "Delete volume transfer in volume_destroy function" into stable/havana
Merge "Raise max header size to accommodate large tokens" into stable/havana