debug: log the info that triggered an update
debug: fix debug output suggesting process leaks

On success, when the supervisor exits, any of its children are updated
in case they weren't previously marked stopped. If they were previously
marked stopped, the usual case, for every ServiceProcess, the following
message would be printed (in debug mode). Under some conditions, this
would be true, but if the process was found, and the stopTime was
already set, this message was wrong and misleading.

    strong-pm:server Got exit event for an unknown process: {"cmd":"exit",...

Fix strongloop-internal/scrum-nodeops#226
debug: don't warn on absence of config file
debug: don't put process.env into the commits

It makes the debug log unreadably long. Instead, merge the commit.env
into process.env just before running.
Merge pull request #84 from strongloop/feature/fix-debug-logging

Fix debug logging
Add Dockerfile for Docker Hub automated build