After configuring a new value set the polling bit to negotiate speeds
again next transmission cycle.
Signed-off-by: Rafael Zalamena <rzalamena@opensourcerouting.org>
When configured transmission speed doesn't match the actual speed, show
the difference in the output.
Signed-off-by: Rafael Zalamena <rzalamena@opensourcerouting.org>
Implement vty shell integration and allow `bfdd` to be configured
through FRR's vtysh.
Signed-off-by: Rafael Zalamena <rzalamena@opensourcerouting.org>
