correct name for basestring in Py3 to 'str' (not 'unicode')

Cython/Compiler/Code.py

@@ -36,9 +36,9 @@ non_portable_builtins_map = {
     # builtins that have different names in different Python versions
     'bytes'         : ('PY_MAJOR_VERSION < 3',  'str'),
     'unicode'       : ('PY_MAJOR_VERSION >= 3', 'str'),
+    'basestring'    : ('PY_MAJOR_VERSION >= 3', 'str'),
     'xrange'        : ('PY_MAJOR_VERSION >= 3', 'range'),
     'BaseException' : ('PY_VERSION_HEX < 0x02050000', 'Exception'),
-    'basestring'    : ('PY_MAJOR_VERSION >= 3', 'unicode'),
     }
 
 basicsize_builtins_map = {