Update Redis to 3.2.5 for security

Update Redis to 3.2.5 as Redis 3.2.1 has a security issue.

Changelog between 3.2.1 and 3.2.5: https://github.com/antirez/redis/compare/3.2.1...3.2.5#diff-484d7b7e500d98f7c1889fbcc6cd2d72

cf.

• #1358 (closed) (Update Redis to 3.2.1)
• #1280 (closed) (Update Redis to 3.2.0)