Ignore redundant PEP8 lint rule: W293
Ignore redundant PEP8 lint rule: W293

Summary:
W293 reports a lint warning for the same problem that TXT6 reports a
lint error for.  This isn't so terrible in and of itself.

However, when you are then prompted to apply a patch to fix TXT6, lint
doesn't realize that the W293 warning was also handled, and still
prompts you about ignoring unresolved warnings.  This is misleading.

Test Plan:
> python pep8.py hasBlankLineWS.py
hasBlankLineWS.py:3:1: W293 blank line contains whitespace
> python pep8.py --ignore=W293 hasBlankLineWS.py
(no output)

Reviewed By: epriestley
Reviewers: jungejason, epriestley
CC: epriestley, aran
Differential Revision: 525

codelabs-ch/arcanist,r4nt/arcanist,PageUpPeopleOrg/arcanist-patches,KieranHayes/arcanist,wxstars/arcanist,folsom-labs/arcanist,folsom-labs/arcanist,wxstars/arcanist,uber/arcanist,Symplicity/arcanist,uber/arcanist,eSpark/arcanist,coursera/arcanist,PageUpPeopleOrg/arcanist-patches,sneakpeeq/arcanist,julkiewicz/arcanist,r4nt/arcanist,sneakpeeq/arcanist,r4nt/arcanist,Symplicity/arcanist,haskell-infra/arcanist,coursera/arcanist,codelabs-ch/arcanist,kevinseelbach/arcanist,aik099/arcanist,kevinseelbach/arcanist,chundongwang/arcanist,alexmv/arcanist,PageUpPeopleOrg/arcanist-patches,phacility/arcanist,Symplicity/arcanist,calblueprint/arcanist,fivestars/arcanist,phacility/arcanist,wharris/arcanist,jra3/arcanist,hach-que/arcanist,calblueprint/arcanist,eSpark/arcanist,kevinseelbach/arcanist,hach-que/arcanist,jra3/arcanist,memsql/arcanist,Symplicity/arcanist,alexmv/arcanist,Khan/arcanist,aik099/arcanist,folsom-labs/arcanist,KieranHayes/arcanist,haskell-infra/arcanist,wharris/arcanist,julkiewicz/arcanist,Khan/arcanist,wikimedia/phabricator-arcanist,zhihu/arcanist,julkiewicz/arcanist,dguo-coursera/arcanist,codelabs-ch/arcanist,chundongwang/arcanist,phacility/arcanist,eSpark/arcanist,jra3/arcanist,aik099/arcanist,chundongwang/arcanist,wharris/arcanist,zhihu/arcanist,fivestars/arcanist,sneakpeeq/arcanist,fivestars/arcanist,coursera/arcanist,Khan/arcanist,calblueprint/arcanist,dguo-coursera/arcanist,PageUpPeopleOrg/arcanist-patches,wharris/arcanist,sneakpeeq/arcanist,aik099/arcanist,julkiewicz/arcanist,zhihu/arcanist,KieranHayes/arcanist,uber/arcanist,dguo-coursera/arcanist,wikimedia/phabricator-arcanist,calblueprint/arcanist,haskell-infra/arcanist,Khan/arcanist,haskell-infra/arcanist,jra3/arcanist,coursera/arcanist,KieranHayes/arcanist,alexmv/arcanist,memsql/arcanist,kevinseelbach/arcanist,r4nt/arcanist,folsom-labs/arcanist,wxstars/arcanist,wxstars/arcanist,chundongwang/arcanist,codelabs-ch/arcanist,phacility/arcanist,dguo-coursera/arcanist,wikimedia/phabricator-arcanist,fivestars/arcanist,codelabs-ch/arcanist,uber/arcanist,alexmv/arcanist,wikimedia/phabricator-arcanist,eSpark/arcanist,memsql/arcanist,phacility/arcanist,memsql/arcanist,zhihu/arcanist,hach-que/arcanist,hach-que/arcanist