Update Redis to 3.2.5

• Update Redis from 3.2.1 to 3.2.5
• Merge redis.conf diff between 3.2.1 and 3.2.5: https://github.com/antirez/redis/compare/3.2.1...3.2.5#diff-1a75827fc1e080d1600e2a6843aa311d

Closes #1665 (closed)