Using Google Authenticator for sshd password login on Linux

Here are the standard instructions:

https://code.google.com/p/google-authenticator/source/browse/libpam/README

I wanted to enter the password and OTP together instead separately for two prompts. This is important for things like connecting to NX through a login password.

On Fedora, I followed the instruction of adding the forward_pass option and it worked like a charm. I had to make sure I had a new-enough version of the RPM, though. v0.3 didn't seem to support the option.