Log Message:
Update redis to 2.4.8.

Changes in 2.4.8
* [BUGFIX] Make install now uses cp -f to avoid 'text file busy' errors.
* [BUGFIX] redis-check-aof is now large files safe also on 32 bit systems.
* [BUGFIX] Issue #327 fixed: maxmemory and replication now work much better.
* [BUGFIX] Now HINCRBY can detect overflows too. Fix for issue #330.
* [BUGFIX] Fixed compilation with latest clang.
* [BUGFIX] Fixed handling of empty sorted sets produced in RDB by
           very old Redis versions (1.2.x).

Changes in 2.4.7
* [BUGFIX] Fixed false positive in issue #141 regression test.
* [BUGFIX] Slave should not expire keys when loading an RDB after a SYNC.
* [BUGFIX] Don't increment stats for key misses / hits when key is written.
* [BUGFIX] sds.c library now don't allocate more than 1MB ahead.
* 32 bit instances without a maxmemory set now get a default limit of 3.5GB
  with maxmemory-policy set to noeviction.
* Better crash report on crash (containing current client and command
  arguments).