Correct iteritems syntax

Author: jborean93

gssapi/_utils.py

@@ -107,7 +107,7 @@ def enc(x):
         else:
             return x
 
-    return dict((enc(k), enc(v)) for k, v in d.iteritems())
+    return dict((enc(k), enc(v)) for k, v in iter(d.items()))
 
 
 # in case of Python 3, just use exception chaining