Fix typo in cinder/db/api.py

The api method quota_destroy_all_by_project() calls the implementation
quota_get_all_by_project()

Change-Id: I11927e1fd29c6248ce755dfd236bf0f9adf39d94
Fixes: bug #1108766
(cherry picked from commit b79e1f485c85cbb16280adc8d590886e25694c87)