Update heka configuration for awsbox

This updates our scripted awsbox setup to latest heka release, and adds a bit better log/process management.  Fixes #352 for fxa-auth-server.

@dannycoates r?

Once this is merged we need to:

  * copy similar logic into fxa-content-server
  * deploy api-accounts, accounts and accounts-latest with the changes (I already did accounts-latest as a test-run)