xunit reporter: don't include attrs in failure tag
xunit reporter: don't include attrs in failure tag

It's not valid according to the junit xsd. Also the message attribute is not valid in the testcase tag, so it's moved to the failure tag.
node-rookie/mocha,villesau/mocha,TimothyGu/mocha,apkiernan/mocha,moander/mocha,ianwremmel/mocha,hoverduck/mocha,mochajs/mocha,kyroskoh/mocha,netei/mocha,nexdrew/mocha,gaye/mocha,JohnnyEstilles/mocha,kyroskoh/mocha,luxe-eng/valet-express.mocha,nightwatchjs/mocha-nightwatch,kyroskoh/mocha,santiagoaguiar/mocha,node-rookie/mocha,pumpupapp/mocha,diydyq/mocha,aaroncrows/mocha,nexdrew/mocha,adamgruber/mocha,luxe-eng/valet-express.mocha,ajaykodali/mocha,kolodny/mocha,wltsmrz/mocha,mysterycommand/mocha,luxe-eng/valet-express.mocha,DeNA/mocha,TimothyGu/mocha,apkiernan/mocha,JohnnyEstilles/mocha,JohnnyEstilles/mocha,hoverduck/mocha,jjoos/mocha,geometrybase/mocha,woodyrew/mocha,rlugojr/mocha,tinganho/mocha,hoverduck/mocha,verkkokauppacom/mocha,apkiernan/mocha,a8m/mocha,a8m/mocha,netei/mocha,moander/mocha,wltsmrz/mocha,youprofit/mocha,nightwatchjs/mocha-nightwatch,jkresner/mocha,sul4bh/mocha,ELLIOTTCABLE/mocha,beatfactor/mocha,hashcube/mocha,mbovel/mocha,beatfactor/mocha,antoval/mocha,KevinTCoughlin/mocha,mbovel/mocha,nightwatchjs/mocha-nightwatch,jjoos/mocha,ryanshawty/mocha,IveWong/mocha,diydyq/mocha,Shyp/mocha,GranitB/mocha,beni55/mocha,a8m/mocha,node-rookie/mocha,menelaos/mocha-solarized,IveWong/mocha,mbovel/mocha,rlugojr/mocha,jasonkarns/mocha,ELLIOTTCABLE/mocha,adamgruber/mocha,GranitB/mocha,adamgruber/mocha,mponizil/mocha,youprofit/mocha,hashcube/mocha,antoval/mocha,duncanbeevers/mocha,jkresner/mocha,gaye/mocha,irnc/mocha,villesau/mocha,imsobear/mocha,jasonkarns/mocha,ianwremmel/mocha,igwejk/mocha,upfrontIO/mocha,mysterycommand/mocha,pumpupapp/mocha,charlie77/mocha,joshski/mocha,Phoenixmatrix/mocha,ryanshawty/mocha,benvinegar/mocha,GabrielNicolasAvellaneda/mocha,Phoenixmatrix/mocha,papandreou/mocha,rstacruz/mocha,charlie77/mocha,cleberar38/mocha,pandeysoni/mocha,antoval/mocha,menelaos/mocha-solarized,GabrielNicolasAvellaneda/mocha,imsobear/mocha,GabrielNicolasAvellaneda/mocha,rstacruz/mocha,aaroncrows/mocha,jbnicolai/mocha,aaroncrows/mocha,rlugojr/mocha,santiagoaguiar/mocha,Shyp/mocha,nexdrew/mocha,boneskull/mocha,upfrontIO/mocha,jasonkarns/mocha,Shyp/mocha,GranitB/mocha,woodyrew/mocha,ajaykodali/mocha,jjoos/mocha,diydyq/mocha,Hacker0x01/mocha,mponizil/mocha,gaye/mocha,mochajs/mocha,phated/mocha,mysterycommand/mocha,GerHobbelt/mocha,beni55/mocha,Hacker0x01/mocha,phated/mocha,villesau/mocha,geometrybase/mocha,outsideris/mocha,tswaters/mocha,beni55/mocha,wltsmrz/mocha,jbnicolai/mocha,KevinTCoughlin/mocha,tinganho/mocha,netei/mocha,kolodny/mocha,cleberar38/mocha,ianwremmel/mocha,verkkokauppacom/mocha,moander/mocha,Khan/mocha,sul4bh/mocha,duncanbeevers/mocha,benvinegar/mocha,upfrontIO/mocha,imsobear/mocha,boneskull/mocha,pandeysoni/mocha,IveWong/mocha,tinganho/mocha,GerHobbelt/mocha,kolodny/mocha,GerHobbelt/mocha,menelaos/mocha-solarized,ELLIOTTCABLE/mocha,Khan/mocha,geometrybase/mocha,cleberar38/mocha,mponizil/mocha,benvinegar/mocha,santiagoaguiar/mocha,KevinTCoughlin/mocha,joshski/mocha,ajaykodali/mocha,DeNA/mocha,irnc/mocha,charlie77/mocha,hoverduck/mocha,pumpupapp/mocha,rstacruz/mocha,igwejk/mocha,verkkokauppacom/mocha,ryanshawty/mocha,pandeysoni/mocha,hashcube/mocha,Phoenixmatrix/mocha,woodyrew/mocha,kevinburke/mocha,boneskull/mocha,Khan/mocha,jkresner/mocha,beatfactor/mocha,jbnicolai/mocha,irnc/mocha,papandreou/mocha,DeNA/mocha,mochajs/mocha,tswaters/mocha,kevinburke/mocha,youprofit/mocha,joshski/mocha,sul4bh/mocha,outsideris/mocha,kevinburke/mocha,phated/mocha,tswaters/mocha,Hacker0x01/mocha