fix for #90, multiple destroy calls are successful
fix for #90, multiple destroy calls are successful

whitelynx/knex,danieltdt/knex,shutterstock/knex,vschoettke/knex,galenandrew/knex,MWGitHub/knex,vellotis/knex,MadcapJake/knex,yelmontaser/knex,olalonde/knex,tschuy/knex,knax/knex-bower,xaka/knex,dieface/knex,willrstern/knex,vellotis/knex,wubzz/knex,tgriesser/knex,elhigu/knex,techniq/knex,fgcartographix/knex,blah238/knex,carragom/knex,statyan/knex,willrstern/knex,realtymaps/knex,lanetix/knex,realtymaps/knex,joepie91/knex,whitelynx/knex,MWGitHub/knex,galenandrew/knex,juanjoLenero/knex,tgriesser/knex,nkt/knex,noodle/knex,ryanwilliamquinn/knex,beppu/knex,jevakallio/knex,faradayio/knex,sanchesic89/knex,joeframbach/knex,abegines/knex,seegno-forks/knex,seegno-forks/knex,socialtables/knex,sanchesic89/knex,whitelynx/knex,CorvusCorrax/knex,MadcapJake/knex,chuym/knex,dieface/knex,knax/knex-bower,tgriesser/knex,tschuy/knex,threadmeup/knex,xaka/knex,jevakallio/knex,statyan/knex,yelmontaser/knex,jamesanthonyferguson/knex,Atlantis-Software/knex,freakynit/knex,maxcnunes/knex,sxhao/knex,myndzi/knex,MadcapJake/knex,socialtables/knex,seegno-forks/knex,nkt/knex,chuym/knex,elhigu/knex,jamesanthonyferguson/knex,vellotis/knex,faradayio/knex,maxcnunes/knex,jevakallio/knex,fgcartographix/knex,WaltRock/knex,chuym/knex,CorvusCorrax/knex,carragom/knex,faradayio/knex,jut-io/knex,socialtables/knex,joeframbach/knex,abegines/knex,olalonde/knex,wubzz/knex,joeframbach/knex,eknkc/knex,jut-io/knex,sanchesic89/knex,realtymaps/knex,MWGitHub/knex,linalu1/knex,lanetix/knex,juanjoLenero/knex,dieface/knex,myndzi/knex,techniq/knex,fgcartographix/knex,chrisbroome/knex,noodle/knex,willrstern/knex,jamesanthonyferguson/knex,threadmeup/knex,Atlantis-Software/knex,lanetix/knex,WaltRock/knex,ryanwilliamquinn/knex,harriha/knex,tschuy/knex,knax/knex-bower,shutterstock/knex,vschoettke/knex,vschoettke/knex,joepie91/knex,olalonde/knex,joepie91/knex,blah238/knex,freakynit/knex,beppu/knex,elhigu/knex,harriha/knex,yelmontaser/knex,linalu1/knex,linalu1/knex,danieltdt/knex,jut-io/knex,danieltdt/knex,chrisbroome/knex,galenandrew/knex,chris-olszewski/knex,shutterstock/knex,chris-olszewski/knex,blah238/knex,techniq/knex,harriha/knex,freakynit/knex,juanjoLenero/knex,beppu/knex,ryanwilliamquinn/knex,chris-olszewski/knex,maxcnunes/knex,sxhao/knex,eknkc/knex,threadmeup/knex,sxhao/knex,eknkc/knex,nkt/knex,xaka/knex,chrisbroome/knex