Fix a bug with sensors - we need to establish a database connection inside the
sensor_wrapper since sensor_wrapper runs inside a separate process.

We need to do this because of changes introduced in
931c238eac087ea84d535df1c3823edfbdfe8eb5
Merge pull request #910 from StackStorm/sensors_triggerwatcher_fix

Fix sensor exploding when TriggerWatching was reading existing Triggers from the database