Log Message:
Update redis to 2.4.9.

Changes in 2.4.9:
* [FEATURE] Redis server is now able to test your memory for broken RAM.
            Usage: ./redis-server --test-memory <megabytes>.
* [FEATURE] redis-benchmark backported from unstable. Pipelining, run selected
            tests, and a few more features.
* [BUGFIX] utils/install_server.sh script now works on Redhat / Centos.
* [BUGFIX] Minor fix to redis-cli (github issue #306).