Our UI allows to provide username and password for ssh:// protocol in separate fields
jGit implementation requires that the username is embedded in the protocol - if it's not, it will be taken from the ssh config.

We should handle this case by changing the uri if we see it's ssh:// and the username is set in the field.

We should at least mark it as an error during form validation - actually, this may be the right approach (signal error only, no uri tweaking)