Hard code logdir/datadir to Ubuntu paths

We should never use the client's OS to
decide how to form paths for the target.
This change hardcodes an Ubuntu series
to generate the paths for now, until
Windows support is in.

Fixes https://bugs.launchpad.net/juju-core/+bug/1342725
Merge pull request #440 from axw/lp1342725-hardcode-ubuntu-paths

Hard code logdir/datadir to Ubuntu paths

We should never use the client's OS to
decide how to form paths for the target.
This change hardcodes an Ubuntu series
to generate the paths for now, until
Windows support is in.

Fixes https://bugs.launchpad.net/juju-core/+bug/1342725