Correct Hacking rule code

The hacking rule error code should be start with 'M', which stands for
Magnum.

PS: Error number begins with M301

Closes-Bug: #1465895
Change-Id: Ie9565c4a700a1bf85eed8c5db87a8c4012f5254b

HACKING.rst

@@ -1,11 +1,11 @@
-magnum Style Commandments
+Magnum Style Commandments
 =========================
 
 - Step 1: Read the OpenStack Style Commandments
   http://docs.openstack.org/developer/hacking/
 - Step 2: Read on
 
-magnum Specific Commandments
+Magnum Specific Commandments
 ---------------------------
 
-- [N301] policy.enforce_wsgi decorator must be the first decorator on a method.
+- [M301] policy.enforce_wsgi decorator must be the first decorator on a method.

magnum/hacking/checks.py

@@ -20,10 +20,11 @@ Guidelines for writing new hacking checks
 
  - Use only for Magnum specific tests. OpenStack general tests
    should be submitted to the common 'hacking' module.
- - Pick numbers in the range N3xx. Find the current test with
+ - Pick numbers in the range M3xx. Find the current test with
    the highest allocated number and then pick the next value.
+   If nova has an N3xx code for that test, use the same number.
  - Keep the test method code in the source file ordered based
-   on the N3xx value.
+   on the M3xx value.
  - List the new rule in the top level HACKING.rst file
  - Add test cases for each new rule to magnum/tests/unit/test_hacking.py
 
@@ -36,7 +37,7 @@ decorator_re = re.compile(r"@.*")
 def check_policy_enforce_decorator(logical_line,
                                    previous_logical, blank_before,
                                    filename):
-    msg = ("N301: the policy.enforce_wsgi decorator must be the "
+    msg = ("M301: the policy.enforce_wsgi decorator must be the "
            "first decorator on a method.")
     if (blank_before == 0 and re.match(enforce_re, logical_line)
             and re.match(decorator_re, previous_logical)):

magnum/tests/unit/test_hacking.py

@@ -1,4 +1,4 @@
-#    Copyright 2915 Intel, Inc.
+#    Copyright 2015 Intel, Inc.
 #
 #    Licensed under the Apache License, Version 2.0 (the "License"); you may
 #    not use this file except in compliance with the License. You may obtain
@@ -82,4 +82,4 @@ class HackingTestCase(base.TestCase):
                    pass
                """
         self._assert_has_errors(code, checks.check_policy_enforce_decorator,
-                                expected_errors=[(2, 0, "N301")])
+                                expected_errors=[(2, 0, "M301")])