Update libmemcached to 1.0.4.

pkgsrc changes:
* Fix build on SunOS
* Add proper libtool support

Upstream changes:

1.0.4
* Fix for memcached_dump().
* Additional testing for memcached_stat_execute().

1.0.3
* Increased size of sort buffer used during Ketama.
* Added support for new behavior to handle dead servers.
* Overall haul of UDP IO.
* Fixed C compile issue with memcached_exist()
* Numerous bug fixes.
* Clang support for OSX.
* All commands now using vector send support.

1.0.2
* Dropped libmemcached/memcached_util.h (undocumented header file)
* Added memcached_touch() and memcached_touch_by_key()
* UDP support restructured to toggle on a complete memcached_st structure.

(fhajny)