Add Victoria and Wallaby releases to versionutils

Now that we have names for the next two releases we can get them
added here so we'll be ready when development starts.

Change-Id: I515a6b03b810a7c8b2246279e380973a29c626f4

oslo_log/versionutils.py

@@ -74,6 +74,8 @@ _RELEASES = {
     'S': 'Stein',
     'T': 'Train',
     'U': 'Ussuri',
+    'V': 'Victoria',
+    'W': 'Wallaby',
 }