processor: extend boot timeout to 4 minutes
processor: extend boot timeout to 4 minutes

10 seconds is way too short for Sauce Labs. This timeout should really
be configurable, but I'm keeping it static for now for ease of
implementation.

Acidburn0zzz/worker,travis-ci/worker,Acidburn0zzz/worker,solarce/worker,henrikhodne-abandoned/worker,solarce/worker,Acidburn0zzz/worker,henrikhodne-abandoned/worker,travis-ci/worker,henrikhodne-abandoned/worker,travis-ci/worker,solarce/worker