Update Redis to 1.951.

Changes:

1.951    2012-03-13T10:17:09Z
    * Remove Tie::StdHash from our dependencies list, its part of core
      and it creates problems with some CPAN clients

1.950    2012-03-12T13:54:10Z
    * DEPRECATED: the encoding attribute to new() - we will not support
      automatic decoding after 2.000, so please test your code with
      encoding => undef now.
    * Add pipeline support: Aaron Crane arc@github++!
    * Cache AUTOLOAD calls: improves performance a bit, fixes #2
    * Fix: apply reconnect logic to KEYS and INFO
    * Fix: forbid PING and SHUTDOWN in SUBSCRIBE mode
    * Updated docs covering pipelining and multi/exec
    * Updated docs to point users to Github for code and issues

(mishka)