Merge branch 'sentinel-psswd-docs' into 'master'

Use master_password for Sentinel

See merge request !10857

doc/administration/high_availability/redis.md

@@ -492,7 +492,7 @@ which ideally should not have Redis or Sentinels on it for a HA setup.
     redis['master_name'] = 'gitlab-redis'
     ## The same password for Redis authentication you set up for the master node.
-    redis['password'] = 'redis-password-goes-here'
+    redis['master_password'] = 'redis-password-goes-here'
     ## A list of sentinels with `host` and `port`
     gitlab_rails['redis_sentinels'] = [