fs.readFile: Emit 'close' if we don't expect a close later

This fixes a regression introduced by 40b7302

lib/fs.js

@@ -88,6 +88,9 @@ fs.readFile = function(path, encoding_) {
   readStream.on('error', function(er) {
     error = er;
     readStream.destroy();
+    if (!readStream.fd) {
+      readStream.emit('close');
+    }
   });
 
   readStream.on('close', function() {