Add log level config to production environment
Add log level config to production environment

We were seeing the following error in the console so adding an explicit
log level line.

    DEPRECATION WARNING: You did not specify a `log_level` in
    `production.rb`. Currently, the default value for `log_level` is
    `:info` for the production environment and `:debug` in all other
    environments.  In Rails 5 the default value will be unified to
    `:debug` across all environments. To preserve the current setting,
    add the following line to your `production.rb`: *** [err ::
    backend-2.backend.production]

    config.log_level = :info

alphagov/release,alphagov/release,alphagov/release