MANTA-850 marlin worker dumps core when mahi goes away (fix test race)
MANTA-850 marlin worker dumps core when mahi goes away (fix test race)

joyent/manta-marlin,davepacheco/manta-marlin,joyent/manta-marlin,davepacheco/manta-marlin,davepacheco/manta-marlin,joyent/manta-marlin