Fix my last commit (r81471) about codecs

Rememder: don't touch the code just before a commit
diff --git a/Lib/encodings/utf_16.py b/Lib/encodings/utf_16.py
index 61bb041..b145a5d 100644
--- a/Lib/encodings/utf_16.py
+++ b/Lib/encodings/utf_16.py
@@ -67,11 +67,11 @@
 
     def encode(self, input, errors='strict'):
         if self.encoder is None:
-            result = codecs.utf_16encoder(input, errors)
+            result = codecs.utf_16_encode(input, errors)
             if sys.byteorder == 'little':
-                self.encoder = codecs.utf_16_leencoder
+                self.encoder = codecs.utf_16_le_encode
             else:
-                self.encoder = codecs.utf_16_beencoder
+                self.encoder = codecs.utf_16_be_encode
             return result
         else:
             return self.encoder(input, errors)