Bug: ssh-copy-id mishandles dropbear

[Norbert Lange]

Hello,

ssh-copy-id has special handling for dropbear, but this seems to be
quite out of date (or forever wrong).
I dont see dropbear ever accessing `/etc/dropbear/authorized_keys`,
and I don't see any hints this ever was the case.

dropbear uses ~/.ssh/authorized_keys just like OpenSSH, so the special
handling needs to go.

regards, Norbert