 Add documentation for DELETE method for Swift Object Store API.
 Add documentation for DELETE method for Swift Object Store API.

   Account API does not document 'DELETE' verb, which is a valid request to
delete an account.
   This is a doc addition request.

 Closes-Bug: 1704200

Change-Id: Iab53c574cc226e9505f28d3443fd7972b90a463a

openstack/swift,tipabu/swift,tipabu/swift,tipabu/swift,openstack/swift,tipabu/swift,openstack/swift,openstack/swift