Work around double callbacks on less errors
Work around double callbacks on less errors

#28

chcokr/less-interop-loader,webpack/less-loader,jakwuh/less-loader,chcokr/less-interop-loader,HQidea/less-loader,next0/less-loader,next0/less-loader,webpack/less-loader,HQidea/less-loader,jakwuh/less-loader