Disabled ZeroMQ logging for the log service itself.

This is temporary: only long polled requests should be suppressed, and then possibly only
until the request is done, otherwise the long polling procedure loses its value, as there
always will be contents to fetch.
Temp fix to inhibit logging for log_service: revert to 'smart' Passenger spawning.
Updated chromedriver.
Merge remote-tracking branch 'upstream/master'