Better way to avoid unlinking a non-existent file.
Better way to avoid unlinking a non-existent file.

This solves a race condition too (although there is still another race),
and is more consistent with similar patterns elsewhere in the file.

Testing Done:
Relevant integration tests pass (after cleaning, so this triggers both a failed unlink and a successful one).

Manually tested the relevant code block.

Reviewed at https://rbcommons.com/s/twitter/r/1438/

foursquare/pants,laurentgo/pants,TansyArron/pants,mateor/pants,areitz/pants,pombredanne/pants,ericzundel/pants,lahosken/pants,baroquebobcat/pants,lahosken/pants,wisechengyi/pants,dgomez10/xanon,peiyuwang/pants,kslundberg/pants,cevaris/pants,landism/pants,ity/pants,dturner-tw/pants,twitter/pants,qma/pants,mateor/pants,sameerparekh/pants,wisechengyi/pants,benjyw/pants,tdyas/pants,wisechengyi/pants,dgomez10/xanon,jessrosenfield/pants,twitter/pants,mateor/pants,peiyuwang/pants,landism/pants,baroquebobcat/pants,pantsbuild/pants,jsirois/pants,scode/pants,dgomez10/xanon,areitz/pants,benjyw/pants,cevaris/pants,twitter/pants,slyphon/pants,mateor/pants,sameerparekh/pants,sid-kap/pants,qma/pants,gmalmquist/pants,qma/pants,fkorotkov/pants,scode/pants,tejal29/pants,UnrememberMe/pants,pombredanne/pants,dturner-tw/pants,digwanderlust/pants,megaserg/pants,peiyuwang/pants,slyphon/pants,twitter/pants,ericzundel/pants,twitter/pants,sid-kap/pants,Gabriel439/pants,kslundberg/pants,tdyas/pants,cevaris/pants,laurentgo/pants,tdyas/pants,fkorotkov/pants,ity/pants,sid-kap/pants,megaserg/pants,kwlzn/pants,ericzundel/pants,pantsbuild/pants,TansyArron/pants,wisechengyi/pants,scode/pants,pombredanne/pants,dbentley/pants,jessrosenfield/pants,UnrememberMe/pants,kslundberg/pants,jessrosenfield/pants,jtrobec/pants,dgomez10/xanon,scode/pants,cevaris/pants,tejal29/pants,qma/pants,pantsbuild/pants,manasapte/pants,tejal29/pants,ericzundel/pants,landism/pants,slyphon/pants,dturner-tw/pants,pombredanne/pants,wisechengyi/pants,pantsbuild/pants,UnrememberMe/pants,slyphon/pants,di0spyr0s/pants,Gabriel439/pants,pgroudas/pants,cevaris/pants,qma/pants,megaserg/pants,manasapte/pants,jtrobec/pants,jessrosenfield/pants,benjyw/pants,sid-kap/pants,peiyuwang/pants,fkorotkov/pants,baroquebobcat/pants,digwanderlust/pants,TansyArron/pants,15Dkatz/pants,manasapte/pants,dgomez10/xanon,slyphon/pants,landism/pants,qma/pants,ity/pants,kwlzn/pants,laurentgo/pants,dgomez10/xanon,kslundberg/pants,jtrobec/pants,ity/pants,jtrobec/pants,benjyw/pants,wisechengyi/pants,UnrememberMe/pants,kwlzn/pants,tdyas/pants,lahosken/pants,dgomez10/xanon,15Dkatz/pants,sameerparekh/pants,dgomez10/xanon,manasapte/pants,lahosken/pants,dturner-tw/pants,digwanderlust/pants,ericzundel/pants,jtrobec/pants,sameerparekh/pants,cevaris/pants,jessrosenfield/pants,laurentgo/pants,areitz/pants,scode/pants,baroquebobcat/pants,manasapte/pants,dturner-tw/pants,jsirois/pants,pantsbuild/pants,15Dkatz/pants,dbentley/pants,landism/pants,sameerparekh/pants,megaserg/pants,gmalmquist/pants,ericzundel/pants,wisechengyi/pants,kslundberg/pants,peiyuwang/pants,jsirois/pants,baroquebobcat/pants,dbentley/pants,Gabriel439/pants,kwlzn/pants,twitter/pants,dgomez10/xanon,dturner-tw/pants,dbentley/pants,pgroudas/pants,ericzundel/pants,pgroudas/pants,areitz/pants,foursquare/pants,baroquebobcat/pants,megaserg/pants,gmalmquist/pants,lahosken/pants,di0spyr0s/pants,twitter/pants,pantsbuild/pants,mateor/pants,TansyArron/pants,peiyuwang/pants,foursquare/pants,TansyArron/pants,qma/pants,laurentgo/pants,fkorotkov/pants,lahosken/pants,UnrememberMe/pants,pantsbuild/pants,pgroudas/pants,gmalmquist/pants,areitz/pants,sid-kap/pants,dbentley/pants,UnrememberMe/pants,tejal29/pants,kslundberg/pants,di0spyr0s/pants,UnrememberMe/pants,gmalmquist/pants,dbentley/pants,TansyArron/pants,ity/pants,sid-kap/pants,jtrobec/pants,gmalmquist/pants,jtrobec/pants,twitter/pants,di0spyr0s/pants,kwlzn/pants,mateor/pants,wisechengyi/pants,jessrosenfield/pants,di0spyr0s/pants,megaserg/pants,foursquare/pants,digwanderlust/pants,benjyw/pants,landism/pants,gmalmquist/pants,benjyw/pants,tdyas/pants,tdyas/pants,mateor/pants,slyphon/pants,laurentgo/pants,tdyas/pants,fkorotkov/pants,fkorotkov/pants,manasapte/pants,Gabriel439/pants,UnrememberMe/pants,foursquare/pants,tdyas/pants,di0spyr0s/pants,baroquebobcat/pants,dgomez10/xanon,digwanderlust/pants,tejal29/pants,15Dkatz/pants,baroquebobcat/pants,sameerparekh/pants,pombredanne/pants,ity/pants,foursquare/pants,mateor/pants,wisechengyi/pants,TansyArron/pants,pgroudas/pants,pombredanne/pants,landism/pants,slyphon/pants,Gabriel439/pants,peiyuwang/pants,digwanderlust/pants,dbentley/pants,landism/pants,kslundberg/pants,foursquare/pants,kwlzn/pants,areitz/pants,twitter/pants,15Dkatz/pants,Gabriel439/pants,lahosken/pants,scode/pants,ity/pants,Gabriel439/pants,megaserg/pants,dgomez10/xanon,fkorotkov/pants,jessrosenfield/pants,fkorotkov/pants,15Dkatz/pants,cevaris/pants,tdyas/pants,15Dkatz/pants,lahosken/pants,scode/pants,dturner-tw/pants,kwlzn/pants,baroquebobcat/pants,UnrememberMe/pants,sameerparekh/pants,benjyw/pants,pgroudas/pants,sid-kap/pants,foursquare/pants,ericzundel/pants,15Dkatz/pants,peiyuwang/pants,areitz/pants,manasapte/pants,pombredanne/pants,foursquare/pants,di0spyr0s/pants