[PATCH] Remove duplicate file in Documentation/networking

The files wanpipe.txt and wan-router.txt in Documentation/networking contain
the exact same information (diff between the two shows no document is "Linux
WAN Router Utilities Package" and therefor the name wan-router.txt is more
appropriate.
Signed-off-by: Tobias Klauser <tklauser@nuerscht.ch>
Signed-off-by: Domen Puncer <domen@coderock.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>