Fixes rescue doesn't honor enable password conf for v3

The rescue api should honor enable_instance_password conf
setting just like server creation and rebuild api does,
enables this flag will returning the instance password from
server API call rescue, If the hypervisor does not support
password injection then the password returned will not be
correct, this patch just fixes v3 rescue api, since change
return value of v2 could potentially break apps which depend
on this being returned.

DocImpact
Closes-bug #1213866

Change-Id: Ie8422979940bbde8c5749fcd3d6c735e88f78c6a
Merge "Fixes rescue doesn't honor enable password conf for v3"
xenapi: refactor: move UpdateGlanceImage to common

During the review of https://review.openstack.org/41651 it was
recommended to move UpdateGlanceImage to a common library. A bug was
filed to deal with the refactors. This change fixes the first part.

Fixes bug 1220596

Change-Id: I95ae89525b7e6768c5a70364945d5a10cb906d88
XenAPI: Fix translation of metadetails in aggregates

https://review.openstack.org/#/c/43157/ added a translation from the sqlalchemy model to
the instance object replacing metadetails with metadata.

This added more traces in general for XenAPI (when we queried whether we were using
aggregates) and actually broke the host aggregate functionality

Change-Id: I87195753931945b6e1ecf75bc81575a6fa03068e
Closes-bug: 1232179
xenapi: post install scriptlet to rpm

A post install script that creates the /images directory on xenserver,
and sets up the trust relationship.

Change-Id: Id57e3a3ab2782550468c6aa4c01059ceb7cc81ab