Capistrano v3 real-time tasks configuration

The configuration on the Capistrano v3 real-time tasks that were added in https://github.com/pat/thinking-sphinx/commit/724d9fd958adacf47c31e6b218a03d15341c48d6 still use the cap v2 task configuration value `:thinking_sphinx_options`. 

The rest of the v3 tasks use `:thinking_sphinx_roles`. 

This PR updates the real-time tasks to use `:thinking_sphinx_roles` to be consistent and not require users to duplicate configuration for the same thing.