remove bountysource badge

README.rst

@@ -171,11 +171,7 @@ see ``docs/support.rst`` in the source distribution).
 
 .. start-badges
 
-|doc| |build| |coverage| |bestpractices| |bounties|
-
-.. |bounties| image:: https://api.bountysource.com/badge/team?team_id=78284&style=bounties_posted
-        :alt: Bounty Source
-        :target: https://www.bountysource.com/teams/borgbackup
+|doc| |build| |coverage| |bestpractices|
 
 .. |doc| image:: https://readthedocs.org/projects/borgbackup/badge/?version=stable
         :alt: Documentation