Use `versionutils.is_compatible` for Dom0 plugin

Related-Oslo-Commit: d7d74a752e34d5249fa47c8e8252da491d46012a
Change-Id: Iffb19f186fe2b239361fc342de0042acfa5e098d
Fixes Hyper-V snapshot spawning issue

In Hyper-V, snapshoting an instance and then spawning a new
one using the resulted snapshot image with the same flavor,
will result an Hyper-V Exception.

Hyper-V will get the request to resize the base image to it's
actual size, leading to an error.

The reason is that the logic of the resize_vhd method has been
changed, as it is meant to resize images to the flavor size minus
the image metadata size, thus it's maximum internal size. For this
reason, the way to decide whether the root image should be resized
or not must also be changed.

So, instead of comparing the root image and base image sizes,
we should compare their maximum internal sizes.

Closes-Bug: #1234759

Change-Id: I83d2df76b726d705cedc52a8309a2be7037d6a79
Merge "Use `versionutils.is_compatible` for Dom0 plugin"
Merge "Fixes Hyper-V snapshot spawning issue"
VMware: Fix ValueError unsupported format character in log message

Fixes a typo with format string in a log message.

Closes-bug: #1240292
Change-Id: Ia86859089351255cb974ed77b0c5f55a5e953b0e
Merge "VMware: Fix ValueError unsupported format character in log message"
Make cells 'flavorid' for resizes

Cells should use 'flavorid' (not 'id') for resizes.

bug 1241222

Change-Id: I57b997425f183f25d3ca032c7d8c35c1f49e3afc
Updated from global requirements

Change-Id: I98c312279426c2f95cefea67260afd1677a11184
Merge "Make cells 'flavorid' for resizes"
Merge "Updated from global requirements"
xenapi: post install scriptlet to rpm

A freshly installed XenServer requires some modifications in order to be
able to run OpenStack. Nova contains an rpm specification to create a
package with the dom0 plugins, however installing the rpm is not enough.
Some more actions need to be taken:
 - create /images, link to a directory within the local SR
 - setup an ssh keypair, and authenticate it with the host
This change adds a post script to the nova plugins rpm spec file, so
by installing the rpm on a XenServer, it is ready to run OpenStack, no
further manual actions needed.

Change-Id: Id57e3a3ab2782550468c6aa4c01059ceb7cc81ab