fix by david roe and nils bruin to not spawn thousands of zombies in docker image
fix by david roe and nils bruin to not spawn thousands of zombies in docker image

tscholl2/smc,DrXyzzy/smc,DrXyzzy/smc,tscholl2/smc,sagemathinc/smc,sagemathinc/smc,sagemathinc/smc,tscholl2/smc,DrXyzzy/smc,DrXyzzy/smc,sagemathinc/smc,tscholl2/smc,tscholl2/smc