Kill the twitter/commons -> pantsbuild/pants migration script.
Kill the twitter/commons -> pantsbuild/pants migration script.

Testing Done:
CI went green here:
  https://travis-ci.org/pantsbuild/pants/builds/64722855

Bugs closed: 1614

Reviewed at https://rbcommons.com/s/twitter/r/2293/

TansyArron/pants,landism/pants,15Dkatz/pants,landism/pants,jtrobec/pants,dbentley/pants,pgroudas/pants,slyphon/pants,dturner-tw/pants,mateor/pants,foursquare/pants,fkorotkov/pants,jessrosenfield/pants,peiyuwang/pants,UnrememberMe/pants,wisechengyi/pants,peiyuwang/pants,di0spyr0s/pants,Gabriel439/pants,pantsbuild/pants,digwanderlust/pants,fkorotkov/pants,areitz/pants,megaserg/pants,kslundberg/pants,kwlzn/pants,di0spyr0s/pants,peiyuwang/pants,wisechengyi/pants,landism/pants,wisechengyi/pants,kwlzn/pants,ity/pants,wisechengyi/pants,tdyas/pants,dturner-tw/pants,areitz/pants,gmalmquist/pants,jessrosenfield/pants,digwanderlust/pants,areitz/pants,ericzundel/pants,TansyArron/pants,twitter/pants,mateor/pants,Gabriel439/pants,landism/pants,pantsbuild/pants,tdyas/pants,15Dkatz/pants,baroquebobcat/pants,gmalmquist/pants,mateor/pants,kslundberg/pants,ericzundel/pants,kwlzn/pants,gmalmquist/pants,baroquebobcat/pants,pombredanne/pants,15Dkatz/pants,sid-kap/pants,UnrememberMe/pants,tdyas/pants,scode/pants,TansyArron/pants,manasapte/pants,gmalmquist/pants,baroquebobcat/pants,fkorotkov/pants,twitter/pants,twitter/pants,pombredanne/pants,benjyw/pants,ity/pants,manasapte/pants,benjyw/pants,dbentley/pants,scode/pants,sameerparekh/pants,qma/pants,sameerparekh/pants,pantsbuild/pants,sid-kap/pants,qma/pants,laurentgo/pants,TansyArron/pants,wisechengyi/pants,areitz/pants,kwlzn/pants,dbentley/pants,pantsbuild/pants,pgroudas/pants,digwanderlust/pants,kslundberg/pants,scode/pants,sameerparekh/pants,laurentgo/pants,jtrobec/pants,sid-kap/pants,ity/pants,fkorotkov/pants,manasapte/pants,di0spyr0s/pants,areitz/pants,ericzundel/pants,lahosken/pants,slyphon/pants,scode/pants,manasapte/pants,peiyuwang/pants,Gabriel439/pants,cevaris/pants,kwlzn/pants,ericzundel/pants,lahosken/pants,manasapte/pants,landism/pants,sameerparekh/pants,foursquare/pants,scode/pants,15Dkatz/pants,scode/pants,peiyuwang/pants,jtrobec/pants,lahosken/pants,ericzundel/pants,dbentley/pants,gmalmquist/pants,digwanderlust/pants,foursquare/pants,dbentley/pants,pgroudas/pants,tdyas/pants,mateor/pants,qma/pants,fkorotkov/pants,UnrememberMe/pants,kwlzn/pants,pombredanne/pants,ericzundel/pants,lahosken/pants,dturner-tw/pants,foursquare/pants,jtrobec/pants,sid-kap/pants,cevaris/pants,UnrememberMe/pants,lahosken/pants,pombredanne/pants,UnrememberMe/pants,twitter/pants,baroquebobcat/pants,slyphon/pants,jsirois/pants,foursquare/pants,ericzundel/pants,kslundberg/pants,mateor/pants,laurentgo/pants,benjyw/pants,fkorotkov/pants,peiyuwang/pants,15Dkatz/pants,jtrobec/pants,kslundberg/pants,megaserg/pants,cevaris/pants,kslundberg/pants,baroquebobcat/pants,twitter/pants,lahosken/pants,pgroudas/pants,laurentgo/pants,twitter/pants,baroquebobcat/pants,laurentgo/pants,baroquebobcat/pants,benjyw/pants,ity/pants,TansyArron/pants,pombredanne/pants,slyphon/pants,Gabriel439/pants,fkorotkov/pants,sid-kap/pants,qma/pants,pombredanne/pants,dbentley/pants,twitter/pants,jessrosenfield/pants,sameerparekh/pants,kslundberg/pants,di0spyr0s/pants,di0spyr0s/pants,wisechengyi/pants,jtrobec/pants,UnrememberMe/pants,mateor/pants,gmalmquist/pants,15Dkatz/pants,sameerparekh/pants,pgroudas/pants,jsirois/pants,UnrememberMe/pants,fkorotkov/pants,dturner-tw/pants,pombredanne/pants,dturner-tw/pants,TansyArron/pants,peiyuwang/pants,kwlzn/pants,Gabriel439/pants,di0spyr0s/pants,qma/pants,benjyw/pants,megaserg/pants,areitz/pants,baroquebobcat/pants,foursquare/pants,UnrememberMe/pants,landism/pants,ity/pants,pgroudas/pants,digwanderlust/pants,di0spyr0s/pants,lahosken/pants,megaserg/pants,mateor/pants,twitter/pants,foursquare/pants,slyphon/pants,manasapte/pants,ericzundel/pants,jessrosenfield/pants,sid-kap/pants,slyphon/pants,foursquare/pants,ity/pants,pantsbuild/pants,wisechengyi/pants,peiyuwang/pants,ity/pants,manasapte/pants,tdyas/pants,scode/pants,pantsbuild/pants,jessrosenfield/pants,megaserg/pants,qma/pants,Gabriel439/pants,tdyas/pants,twitter/pants,cevaris/pants,UnrememberMe/pants,sameerparekh/pants,jsirois/pants,cevaris/pants,wisechengyi/pants,tdyas/pants,dturner-tw/pants,TansyArron/pants,benjyw/pants,qma/pants,wisechengyi/pants,dturner-tw/pants,jessrosenfield/pants,mateor/pants,digwanderlust/pants,slyphon/pants,cevaris/pants,15Dkatz/pants,megaserg/pants,15Dkatz/pants,cevaris/pants,sid-kap/pants,gmalmquist/pants,jtrobec/pants,landism/pants,benjyw/pants,foursquare/pants,landism/pants,jessrosenfield/pants,Gabriel439/pants,lahosken/pants,areitz/pants,dbentley/pants,pantsbuild/pants,megaserg/pants,laurentgo/pants,tdyas/pants,tdyas/pants,baroquebobcat/pants