slapos/recipe/redis: Add support for UNIX sockets
It is well known that UNIX sockets are faster than TCP over loopback. For example for our std shuttles they have 2 times lower latency and ~ 2-3 times more throughput compared to TCP over loopback (details are in commit log).
Because of lower latencies and higher throughput, for performance reasons, it makes sense to interconnect services on one machine via unix sockets and talk via TCP only to outside world.
Here we add support for unix sockets to Redis recipe.
NOTE the patches are based on not-yet-merged recent Redis update (see !26 (closed)).
Thanks beforehand for feedback,