Support Juju + KVM with a package

[Curtis Hovey-Canonical]

Just as we settled checking for the juju-local package when
bootstrapping an lxc environment. I see the same kind of problem
affects Juju KVM users.We don't have a juju-local-kvm package though.

Juju users are seeing instructions to install missing packages when
they bootstrap a KVM env.They may try several times before they
install every package needed to bootstrap. Users who have upgraded
their KVM envs may have broken their envs because new deps were not
installed on the host machine.

I propose we create a juju-local-kvm package. juju will only check for
that package when bootstrapping. Users will not be able to upgrade or
bootstrap until that package is installed. I can add the package to
the juju packaging branch.

-- 
Curtis Hovey
Canonical Cloud Development and Operations
http://launchpad.net/~sinzui