local_site_reverse was able to take a LocalSite's name, or a request

object, but if you actually had a LocalSite (or None), you'd have to

write your own conditional to extract the name and pass it.
Now, local_site_reverse can take a LocalSite. This saves a database

query, if one is already available, and simplifies calling code.

Unit tests pass.
Used this with another change I'm about to put up.