scp: add option to automatically accept signature

[teknoraver]

Add an -y option which automatically accepts the host key without checking as we did with ssh in commit cd0a08896c83ab20f7cc04e755ce38b1525d47a3

[Ansuel]

@mkj sorry for the tag. Any problem with this simple patch?

[mrkiko]

Yeah - would be very nice to see this merged :)

[mkj]

I wonder if it would be better to have -o StrictHostKeyChecking=off rather than adding another extra flag?

[teknoraver]

That's to be coherent with ssh, which already supports the -y flag

[okashany]

Hi, is there any reason why this patch was not merged?

[mkj]

I'm reluctant to let scp diverge from the flags in upstream OpenSSH - I don't really want to maintain it myself (even OpenSSH have mostly given up on it).

Generally I think the argument lists of dropbear and dbclient are getting unwieldy, so options that aren't usually typed by hand should go under -o instead. Of course dropbear itself doesn't have -o support yet, but one day it will.

[stokito]

Related to #41 that adds -o and #269 that adds to the dbclient -o StrictHostKeyChecking

[mkj]

scp -o stricthostkeychecking should work since #269