Revert "Poll Glance directly for image information"

This reverts commit 1ade39f86f5f5bdb45fc42b5d6d2e508f36433f2.

This code really didn't seem quite "ready for prime time" so
reverting for the time being. Will update and reintroduce soon.
Merge pull request #328 from rackerlabs/revert-glance-polling

Revert "Poll Glance directly for image information"