Increase length of max subreddit name in validator

"internationalpolitics" is longer than 20 chars

r2/r2/controllers/validator/validator.py

@@ -421,7 +421,7 @@ class VCssMeasure(Validator):
     def run(self, value):
         return value if value and self.measure.match(value) else ''
 
-subreddit_rx = re.compile(r"\A[A-Za-z0-9][A-Za-z0-9_]{2,%s}\Z" % Subreddit.MAX_SRNAME_LENGTH)
+subreddit_rx = re.compile(r"\A[A-Za-z0-9][A-Za-z0-9_]{2,20}\Z")
 
 def chksrname(x):
     #notice the space before reddit.com

r2/r2/models/subreddit.py

@@ -86,9 +86,7 @@ class Subreddit(Thing, Printable):
     gold_limit = 100
     DEFAULT_LIMIT = object()
 
-    # Note: this value can increase but should never go down or it won't match
-    # names already in the db
-    MAX_SRNAME_LENGTH = 20
+    MAX_SRNAME_LENGTH = 200 # must be less than max memcached key length
 
     # note: for purposely unrenderable reddits (like promos) set author_id = -1
     @classmethod