Automatically initialise elasticsearch.

Charmstore will now automatically initialise elasticsearch when starting up.
This ensures that elasticsearch will always have the correct index and mapping
configuration required for correct operation.
I think this is great. The less flags the better. Especially as these mappings are tied intimately to the code, so only useful to someone that intimately involved in development of the charm store.

If we want to be able to try out new mappings, you'll need to re-run the charmstore, and it's easy to change them in the code, I think.