Pass test suite against Redis 2.6.x

Plus a bit better Redis version detection.
This is realy incosistant -- you make test sleep for a 10 seconds and "not sure" that the value would be greater than 1?
I think it would be better to keep this test as is and add a copy for `REDIS_VERSION < (2, 8, 0)` with a 10 seconds sleep and proper result check.