Reuse get_bytes_{read,written}() in status.c
This patch uses the get_bytes_{read,written}() functions in the heartbeat code. These functions were introduced at the same time that the heartbeat code was introduced.
You can find the patch in the heartbeat branch of my gitorious mytor repository, or here: http://gitorious.org/mytor/mytor/commit/c2d9d80a072ab586ba97159f1d401b9ed2980b2d