[OE-core] Please review dropbear ssh expired password dialog

[Joseph Reynolds]

FYA, the dropbear SSH server "expired password dialog" patch is ready 
for review.  With this patch, if you ssh into the dropbear server 
(configured to use Linux PAM) and your password is expired, the SSH 
server lets you change your password while logging in. (Before this 
patch, dropbear would announce your password is expired, but not let you 
change it, and not give you access.)

The first email is the patch.  The second email has review materials.
https://lists.ucc.gu.uwa.edu.au/pipermail/dropbear/2019q4/002174.html
https://lists.ucc.gu.uwa.edu.au/pipermail/dropbear/2019q4/002175.html

Please take a look.

- Joseph