Updated stty session state save to check for an interactive terminal

[mingers]

This prevents stty throwing errors (like 'stty: standard input: Invalid argument') in the output when run in a non-interactive session (like via Jenkins).

[delano]

Thanks. One note: you need to leave the rescue in there b/c there are cases where calling stty fails.

[mingers]

Sorry, I thought that was how you were managing non-interactive. I'll add it back in

[delano]

np, thanks!