Ssh fingerprint fix
Created by: raphendyr
We should check exit status instead of look sting n output.
Someone need to validate the tests as I wrote them without testing...
I tested manually the code, so it works.
This should be merged to 4-1-stable and 4-2-stable too, as I think this is security update.
If this patch is not used, users might get gitolite (or any other) system in blocked state.