Use osapi_glance_link_prefix for image location header

When an image is created the location header returned is generated based
on the request url that nova-api receives.  If SSL termination happens
upstream the request url is an http request, and the location header is
wrongly generated with that.  The osapi_glance_link_prefix config option
is available for almost precisely this purpose, so let's use it.

Change-Id: I24e46ed8fc0763f9ddeec65e0d79590dd7b86bef
Closes-bug: 1298005
Fix bug detach volume fails with "KeyError" in EC2

Modified volume['instance_uuid'] to volume.get('instance_uuid'),
to avoid "KeyError", when detach a volume with "attaching" status.

Change-Id: Ic1aacab212c2a2026d18ef57ad9d77fdc6d86b47
Closes-Bug: #1280532
Read deleted instances during lifecycle events

This prevents us from failing to find the associated instance if
the lifecycle event happens after the instance has been deleted,
as in the case of a ... delete.

Change-Id: I819ddf8ff68edc407d7932bf43771c440f514f26
Closes-bug: #1304968
Merge "Read deleted instances during lifecycle events"
Merge "Use osapi_glance_link_prefix for image location header"
Merge "Fix bug detach volume fails with "KeyError" in EC2"