Remove internal store references from migration 015

Migration 015 was accessing a object internal to the swift store driver
and changing its behavior in order to do the migration.  This worked but
it made the assumption that the driver logic would not change without
also changing the migration code.  These two should not be dependent
upon each other.  This patch removes all dependencies on swift from the
migration code.

Fixes bug: 1025746
Change-Id: Ic9559ae809b8784d0992cb5275d3911a725110c8
scrubber: dont print URI of image to be deleted

Print the ID not the URI of the image to to be scrubbed
as the URI can contain credentials

fixes bug lp# 1171851

Change-Id: Ice2d3d25a23bae31380759b87b50228ba358dcf1
Functional tests use a clean cached db that is only created once.

This eliminates the need for 'glance-manage db_sync' to be called
once (and often twice) for every test.  db_sync is an expensive
operation because it must walk through ever database migration.
With this patch, the first time the db is created it is cached
before it is used.  Instead of creating the db in future tests
the cached file is copied.  An atexit() function is used to clean
up the file when the tests are complete.

fixes bug: 1172475
blueprint: refactoring-better-faster-stronger-functional-tests

Change-Id: I96e35c640256bf27ff17da0b5f558bda02906a07
Merge "scrubber: dont print URI of image to be deleted"
Merge "Remove internal store references from migration 015"