Clean up data when store receiving image occurs error

Clean up already received data from backend store to prevent potential
leaking when driver receiving image occurs error such as
ImageSizeLimitExceeded exception.

Fixes bug: 1214276

Change-Id: Ice1de4d1c61a62fff778acbbeb9bc27d03ed7ab4
Signed-off-by: Zhi Yan Liu <zhiyanl@cn.ibm.com>
Scrubber refactoring

* Adding multiple locations image support.
* Adding lock protection to prevent race condition between glance-api
and glance-scrubber service.
* Refactoring scrub queue code.

Implement bp: glance-scrubber-refactoring
docImpact

Change-Id: I050ff212d73ace8e84dcd800245b608210d6b29a
Signed-off-by: Zhi Yan Liu <zhiyanl@cn.ibm.com>
Merge "Clean up data when store receiving image occurs error"