Prevent E305 on variable names class* and def*

Prevent lines like 

    classification_error = 0 

From becoming treated as a class.

Author: ParthKolekar

testsuite/E30not.py

@@ -151,3 +151,7 @@ class Bar(object):
 
 if __name__ == '__main__':
     foo()
+#: Okay
+classification_errors = None
+#: Okay
+defined_properly = True