[PATCH] relayfs: Documentation cleanup, remove obsolete info

librelay and relay-app.h have been retired - update Documentation to reflect
that.

Signed-off-by: Tom Zanussi <zanussi@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>