avoid auto-accepting pair requests from friends already paired with

Unless the request is for repo uuid we already know. This way, if A1 pairs
with friend B1, and B1 pairs with device B2, then B1 can request A1 pair
with it and no confirmation is needed. (In future, may want to try to do
that automatically, to make a more robust network.)

doc/bugs/xmpp_needs_one_account_per_distinct_repository.mdwn

@@ -71,7 +71,7 @@ Some possible fixes:
 2. Or, only auto-accept pair requests from friends we're already paired with
    when they come from a repository whose UUID we already know. This
    enhancment to fix #1 makes it easier to build more robust networks of
-   repositories.
+   repositories. **done**
 
 Hmm, I don't think those fixes are sufficient. Suppose they're in place.
 Then when Alice shares A2 with Bob, both his repositories will ask him to
@@ -101,3 +101,7 @@ So, we need another fix:
 
   Or there could be a warning about account reuse. Doesn't seem likely to
   be effective.
+
+-----
+
+> [[done]]. I've put in the fixes around pairing with friends. --[[Joey]]