Fix AttributeError referring to enabled_extensions

Release v2.5.4

CHANGES.rst

 CHANGES
 =======
 
+2.5.4 - 2016-02-11
+------------------
+
+- **Bug** Missed an attribute rename during the v2.5.3 release.
+
 2.5.3 - 2016-02-11
 ------------------
 

flake8/__init__.py

-__version__ = '2.5.3'
+__version__ = '2.5.4'

flake8/engine.py

@@ -216,7 +216,7 @@ def _parse_multi_options(options, split_token=','):
 
 def _disable_extensions(parser, options):
     ignored_extensions = set(getattr(parser, 'ignored_extensions', []))
-    enabled = set(_parse_multi_options(options.enabled_extensions))
+    enabled = set(_parse_multi_options(options.enable_extensions))
 
     # Remove any of the selected extensions from the extensions ignored by
     # default.