Remove SIGTERM note from memcached docs

As of 1.4.22, it's FIXED UPSTREAM! :tada:

memcached/content.md

@@ -27,11 +27,3 @@ variables generated by the link as well as through DNS as `memcache` from
 `/etc/hosts`.
 
 For infomation on configuring your memcached server, see the extensive [wiki](https://code.google.com/p/memcached/wiki/NewStart).
-
-# Known Issues
-
-As of 1.4.21, memcached does not handle `SIGTERM`, so a standard `docker stop`
-will not stop it gracefully, but will resort to `SIGKILL` after the 10 second
-timeout.  Use `docker kill -s INT` to do a clean stop of the memcached
-container.  There is [a PR](https://github.com/memcached/memcached/pull/88) to
-change this behavior upstream.