trivial bugs in usermux

[OKUJI Yoshinori]

  I guess that Miles just copied most code from hostmux when he wrote
usermux, since usermux still has wrong comments in its code:

izzy@usermux% grep host *.[ch]
mux.c:/* Free storage allocated consumed by the host mux name NM, but not the node
usermux.c:/* Multiplexing filesystems by host
usermux.h:/* Multiplexing filesystems by host
usermux.h:/* The state associated with a host multiplexer translator.  */

You can fix these only by sed.

Thanks,
Okuji