Removed ConfigError type, not needed anymore

Author: JeremyC-za

lib/doorkeeper/errors.rb

@@ -44,7 +44,6 @@ def initialize(response)
     UnableToGenerateToken = Class.new(DoorkeeperError)
     TokenGeneratorNotFound = Class.new(DoorkeeperError)
     NoOrmCleaner = Class.new(DoorkeeperError)
-    ConfigError = Class.new(DoorkeeperError)
 
     InvalidToken = Class.new(BaseResponseError)
     TokenExpired = Class.new(InvalidToken)