redis: add new recipe for redis-2.6.9

A recipe for Redis 2.6.9, an advanced key-value store.
Needed some patching of Makefiles and deps to get it to work with OE.

OE Specific configuration: This is built to override MALLOC and use
    libc's malloc instead of the provided jemalloc or tcmalloc that
    weren't building correctly.

    Also the default savepoint setting was updated in the default
    redis.conf to tune for a small embedded system.

Known Bug: redis-cli eats all the input on a serial port - watch out
    when using the serial console with redis-cli.
    see https://github.com/antirez/linenoise/issues/38

Tested with Yocto "Danny" / armv7a.

Signed-off-by: Kevin Baker <kevinb@ventureresearch.com>
redis: add recipe for redis-2.6.9