[lint] Remove obsolete mainfile var declaration

Author: ixti

lib/mincer/base.js

@@ -206,7 +206,7 @@ Base.prototype.resolve = function (logicalPath, options, fn) {
   if (fn) {
     search = this.attributesFor(logicalPath).searchPaths;
     return this.__trail__.find(search, options, function (pathname) {
-      var bower, extname, mainfile;
+      var bower, extname;
 
       if (!_.contains([ 'component.json', 'bower.json' ], path.basename(pathname))) {
         return fn(pathname);