Do not ask Twilio to record in initial make_call call (tests green)

This PR removes an extraneous use of Twilio's RECORD feature; since we're already transcribing (which yields a recording) we don't need to tell it to record here also.

Tested on staging and confirmed in Twilio logs that we've moved from 2 recordings per text to 1 recording:

![screen shot 2014-08-07 at 1 56 22 pm](https://cloud.githubusercontent.com/assets/994938/3849021/6e569bd0-1e75-11e4-91f9-9896cf644e39.png)