Imported Upstream version 2.8.4
Merge tag 'upstream/2.8.4'

Upstream version 2.8.4

* tag 'upstream/2.8.4':
  Imported Upstream version 2.8.4
New upstream version.
Sync debian/redis.conf.
Also ship redis-sentinel (Closes: #735272)
releasing version 2:2.8.4-1