node 4.x worker exit failure

[davidlehn]

With node 4.2+ (likely earlier 4.x too) all bedrock processes have an exiting problem.

• api.exit() called.
• Worker disconnect() called.
• Cluster exit event handler gets event for same worker id but worker.suicide is false. According to https://nodejs.org/api/cluster.html it seems like it should be true.
• Process prints critical error saying it got code 0.
• Process exists with code 1.

[davidlehn]

nodejs/node#3238

[davidlehn]

Fixing by calling kill() instead of disconnect() and process.exit():
466c8a6