Remove goal keyword from CLI help.
Remove goal keyword from CLI help.

./pants -h still recommended './pants goal goals'.
Now corrected to './pants goals'.

Testing Done:
PANTS_DEV=1 ./pants test tests/python/pants_test::
   733 passed, 4 skipped, 5 xfailed, 3 xpassed...

12:25:45 14:10     [junit]
12:25:45 14:10     [specs]
               SUCCESS
Travis passed: https://travis-ci.org/pantsbuild/pants/builds/49205121

Reviewed at https://rbcommons.com/s/twitter/r/1699/

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