Addresses issue https://github.com/pantsbuild/pants/issues/1202
Addresses issue https://github.com/pantsbuild/pants/issues/1202

options_bootstrapper.py will register the constant "WARN" as a synonym for
"WARNING". This has a side effect of changing the output of the test.

Testing Done:
ran:

```
PANTS_DEV=1 ./pants test ./tests/python/pants_test/option ./tests/python/pants_test/logging
```

and

```
PANTS_DEV=1 ./pants test ./tests/python/pants_test/logging
```

Before this change, the first invocation failed.

Bugs closed: 1202, 1203

Reviewed at https://rbcommons.com/s/twitter/r/1866/

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