Remove confusing message from repo sync output

Someone pointed out this message isn't always the truth; so we
shouldn't print it.  The code path is executed when there are
published commits, yet our output talks about unpublished ones.

Signed-off-by: Shawn O. Pearce <sop@google.com>

project.py

@@ -637,7 +637,6 @@ class Project(object):
                        "branch %s is published but is now %d commits behind",
                        branch.name,
                        len(upstream_gain))
-          syncbuf.info(self, "consider merging or rebasing the unpublished commits")
         return
       elif upstream_gain:
         # We can fast-forward safely.