tipc: Remove support for per-connection message sequence numbering

Eliminates TIPC's prototype support for message sequence numbering
on routable connections (i.e. connections requiring more than one hop).
This capability isn't currently used, and can be removed since TIPC
only supports systems in which all inter-node communication can be
achieved in a single hop.

Signed-off-by: Allan Stephens <Allan.Stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>