Extract cloudinit.MachineConfig constructor.
Satisfying that TODO.
Factor MachineConfig construction out of EC2 provider.
Factor MachineConfig construction out of OpenStack provider.
Update for landing of var-lib-juju branch.
Merge trunk, resolve conflicts.
Merge trunk.
Merge trunk, resolve conflicts.
Always use service name plus AZURE_DOMAIN_NAME as an instance's DNS name.  No more label dance.
Test for the new contents of the service's Label.
[r=jtv] Constructor for cloudinit.MachineConfig.

This is preparation for a refactoring discussed with William Reade and
outlined in bug 1199847. Much of the work of creating a
cloudinit.MachineConfig is repetitive between providers, so we might as well
extract it. This also makes it easier to move the construction from one
function to another, as is likely to happen during the further refactoring.

You'll see that "tools" is not a parameter. That's because the projected
refactoring moves construction of the MachineConfig ahead of where the tools
are selected. If these two steps end up fitting together, uniformly across
providers, once the code starts to stabilize again then we can make "tools" a
parameter after all.
Implment empty methods, use temporary image.
Fix typo.
An instance can now get its service name, rather than its deployment ID, from the WALA config.
Format.
s/saucy/Saucy/
Resolved conflict.
Update comment as per review.
[r=rvb] Azure provider: implement more methods

This branch does two things:
- it replaces the panic() calls in the port-related methods with empty methods. The goal here is to be able to test the provider more easily, provided that you open/close the ports manually.
- it updates the name of the image used because an image with support for Azure in cloud-init has just been made available.

In case you wonder, the change s/ExtraSmall/Small is there to accomodate installing mysql on a node. ExtraSmall does not have enough memory.

This is all for the sake of testing, all of the code that this branch changes will be re-worked later.
Documentation change as per review.