GRADLE-3133 Limit ssh authentication methods to password

Gradle JSch was configured by default to support "gssapi-with-mic,publickey,keyboard-interactive,password" authentication. But "password" is the only one that works at the moment.
A server that allows "publickey,keyboard-interactive" returns "Auth Cancel" by the "keyboard-interactive" method. This is fixed by the pull request.
Additionally, the exception message is changed to let the user know that that one failure cause is that the server is not configured to use "password" authentication.