remove the callback from node.cat, node.fs.cat

src/file.js

@@ -4,7 +4,7 @@ node.fs.exists = function (path, callback) {
   p.addErrback(function () { callback(false); });
 }
 
-node.fs.cat = function (path, encoding, callback) {
+node.fs.cat = function (path, encoding) {
   var open_promise = node.fs.open(path, node.O_RDONLY, 0666);
   var cat_promise = new node.Promise();
 
@@ -12,7 +12,7 @@ node.fs.cat = function (path, encoding, callback) {
 
   open_promise.addErrback(function () { cat_promise.emitError(); });
   open_promise.addCallback(function (fd) {
-    var content = (encoding == node.UTF8 ? "" : []);
+    var content = (encoding === node.UTF8 ? "" : []);
     var pos = 0;
 
     function readChunk () {

src/util.js

@@ -24,10 +24,10 @@ node.encodeUtf8 = function (array) {
   return String.fromCharCode.apply(String, array);
 };
 
-node.cat = function(location, encoding, callback) {
+node.cat = function(location, encoding) {
   var url_re = new RegExp("^http:\/\/");
   var f = url_re.exec(location) ? node.http.cat : node.fs.cat;
-  return f(location, encoding, callback);
+  return f(location, encoding);
 };
 
 node.path = new function () {