Stop allowing password authentication over SSH

For a service like Gerrit Code Review, it just doesn't make much
sense to offer password authentication for users.  Anyone who sets up
an account with us can configure an SSH key and use that for login.

Change-Id: I93373e0a69a7d9adf48001d58983dc8233dcf22e
Signed-off-by: Shawn O. Pearce <sop@google.com>
3 files changed