Fix jshint warning
Fix jshint warning

Nastarani1368/less.js,SomMeri/less-rhino.js,xiaoyanit/less.js,less/less.js,ridixcr/less.js,SomMeri/less-rhino.js,foresthz/less.js,Synchro/less.js,Synchro/less.js,ahstro/less.js,gencer/less.js,SkReD/less.js,arusanov/less.js,SkReD/less.js,ridixcr/less.js,chenxiaoxing1992/less.js,bendroid/less.js,chenxiaoxing1992/less.js,gencer/less.js,bendroid/less.js,mcanthony/less.js,waiter/less.js,seven-phases-max/less.js,mcanthony/less.js,foresthz/less.js,less/less.js,miguel-serrano/less.js,waiter/less.js,Nastarani1368/less.js,xiaoyanit/less.js,christer155/less.js,ahstro/less.js,bammoo/less.js,bammoo/less.js,arusanov/less.js,seven-phases-max/less.js,less/less.js,NaSymbol/less.js,christer155/less.js,evocateur/less.js,miguel-serrano/less.js,evocateur/less.js,NaSymbol/less.js