Remove unused methods from project.ReviewableBranch

These used to be used back when we had Gerrit 1.x support and used
HTTP based uploads to transmit changes for review.  Since we moved
entirely to Gerrit 2.x, these are no longer called.

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

project.py

@@ -140,16 +140,6 @@ class ReviewableBranch(object):
                                  self.replace_changes,
                                  people)
 
-  @property
-  def tip_url(self):
-    me = self.project.GetBranch(self.name)
-    commit = self.project.bare_git.rev_parse(R_HEADS + self.name)
-    return 'http://%s/r/%s' % (me.remote.review, commit[0:12])
-
-  @property
-  def owner_email(self):
-    return self.project.UserEmail
-
 
 class StatusColoring(Coloring):
   def __init__(self, config):