cvsps: add two more tiebreakers in cscmp

test-convert-cvs.t has been a little flaky for a while now. Add an
extra tiebreaker in cscmp so that all the cases in the test will sort
reliably.

Without this patch, test-convert-cvs.t failed after 346 runs. With
this patch, I stopped trying to get it to fail after 615 runs. While
not conclusive, that makes me pretty optimistic that this is a working
fix.

hgext/convert/cvsps.py

@@ -631,7 +631,19 b' def createchangeset(ui, log, fuzz=60, me'
                     odd.add((l, r))
                 d = -1
                 break
+        # By this point, the changesets are sufficiently compared that
+        # we don't really care about ordering. However, this leaves
+        # some race conditions in the tests, so we compare on the
+        # number of files modified and the number of branchpoints in
+        # each changeset to ensure test output remains stable.
 
+        # recommended replacement for cmp from
+        # https://docs.python.org/3.0/whatsnew/3.0.html
+        c = lambda x, y: (x > y) - (x < y)
+        if not d:
+            d = c(len(l.entries), len(r.entries))
+        if not d:
+            d = c(len(l.branchpoints), len(r.branchpoints))
         return d
 
     changesets.sort(cscmp)