sshtunnel: StrictHostKeyChecking for Dropbear

sshtunnel: StrictHostKeyChecking for Dropbear

The dbclient doesn't support the -o StrictHostKeyChecking but it has it's own -y option:
-y    Always accept remote host key if unknown
-y -y Don't perform any remote host key checking (caution)

So we can add these options to make the StrictHostKeyChecking working.
The dbclient will ignore -o StrictHostKeyChecking but use the -y or -yy instead.

The only problem is that the -y flag is also used by the openssh-client:

-y Send log information using the syslog(3) system module.  By default this information is sent to stderr.

This is not critical and once the dbclient start to support the StrictHostKeyChecking we can remove the -y flag.

Signed-off-by: Sergey Ponomarev <stokito@gmail.com>