lib/vty: add vty_stdio at-close hook

This is intended to be used for either "exit on close", "fork on close"
or "reopen vty on close" functionality for the stdio vty.  Which of
these options to take depends on the context, the use case right now is
test programs exiting on EOF.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
2 files changed