Refactor: libcrmcommon: Rename pcmk__get_sbd_timeout()

...to pcmkget_sbd_watchdog_timeout(). For symmetry with
pcmkget_stonith_watchdog_timeout().

Also bounds-check the unsigned int value in
pcmk__accept_remote_connection().

Signed-off-by: Reid Wahl <nrwahl@protonmail.com>