Log Message:

Upadate redis to 2.2.2

Changelog:
* Now Redis has a clean, powerful, supported C library: hiredis.
* Specially encoded data types, small lists and sets can now use up to an order \ 
of magnitude less memory.
* VM partial rewrite for code cleaness and memory usage.
* Change to the implementation of the top level dictionary for better memory \ 
efficienty.
* Sorted sets are now less memory hungry.
[...] 
see https://github.com/antirez/redis/raw/2.2/00-RELEASENOTES for all changes