Reap processes and close fds when exec fails
Reap processes and close fds when exec fails

Fixes OHAI-455: http://tickets.opscode.com/browse/OHAI-455

bougyman/ohai,juliandunn/ohai,chef/ohai,n-marton/ohai,Fodoj/ohai,jaymzh/ohai,btm/ohai,criteo-forks/ohai,glennmatthews/ohai,mattray/ohai,jaymzh/ohai,davide125/ohai,375gnu/ohai,jseely/ohai,criteo-forks/ohai,johnbellone/ohai,sh9189/ohai,tas50/ohai-1,acaiafa/ohai,shtzr840329/ohai,sh9189/ohai,nathwill/ohai,jseely/ohai,Juniper/ohai,phreakocious/ohai,cmluciano/ohai,dreamnite/ohai,http-418/ohai,higanworks/ohai,zshuo/ohai,higanworks/ohai,acaiafa/ohai,davide125/ohai,btm/ohai,shtzr840329/ohai,Juniper/ohai,adamleff/ohai,tas50/ohai-1,chef/ohai,numericillustration/ohai,dreamnite/ohai,adamleff/ohai,jbfavre/ohai,mattray/ohai,nathwill/ohai,broadinstitute/ohai,n-marton/ohai,MSOpenTech/ohai,jbfavre/ohai,juliandunn/ohai,Fodoj/ohai,cmluciano/ohai,numericillustration/ohai,zshuo/ohai,johnbellone/ohai,phreakocious/ohai,375gnu/ohai,MSOpenTech/ohai,glennmatthews/ohai,broadinstitute/ohai,http-418/ohai,bougyman/ohai