[Ffe] Standing feature freeze exception for the 15.04 cycle

Hello,

LXD is a very young project, that's very actively worked on with almost weekly upstream releases scheduled for at least the next month or so.

The goal is to have all the features required for users to play with it in 15.04 by the time we release, however we've only managed to get the 0.1 release out before Feature Freeze.

As this is a universe package with no reverse dependencies other than nova-compute-lxd (which is still in NEW I believe and is worked on by the same team), we'd appreciate it if we could keep on landing upstream releases as they happen until we get close to release.

This is a one-off thing. I believe the team has a pretty good track record of carefully planning and respecting the Ubuntu freezes for its other projects (lxc, cgmanager, lxcfs) and as we have a more mature project for 15.10, we won't be needing that kind of wide blanket exception anymore.

Some of the features we'll be landing upstream by release time:
 - Container configuration
 - Configuration profiles
 - Live migration
 - Keep on implementing the command line tool
 - Cross-host operations (moving containers, profiles, snapshots, images, ...)

LXD 0.1 as it is in Ubuntu today is hardly usable, hardcodes most of its behavior and only builds on i386 and amd64. LXD 0.2 will be much closer to the experience we actually want to provide, less hardcoding and has been tested to build on i386, amd64, armhf and powerpc. We have submitted patches to some of our dependencies to get arm64 working and are still working on ppc64el.