Till now glance was dependent on periodic job to get image
cached locally and also has dependency on ``cachemanage``
middleware for the same.
This patch removes the periodic job and dependency of
``cachemanage`` middleware and initiates immediate caching
of an image via ``PUT /cache/image_id`` API call.
Co-Author: Dan Smith <dms@danplanet.com>
Implements: blueprint instant-caching
Change-Id: I9ab3f1b7595e22dbb03af95168314352a44eb930