ControlPort GETCONF does not recognize command aliases

Because commands passed to GETCONF are not looked-up in the aliases table with expand_abbrev(), we reject GETCONF requests for options that would be valid (though deprecated) if they were used in a torrc.

For example, GETCONF AllowInvalidNodes works whereas GETCONF AllowUnverifiedNodes fails. AllowUnverifiedNodes is a deprecated alias for AllowInvalidNodes.

I propose fixing this by having handle_control_getconf() first call expand_abbrev() on the option it's going to look up. I'll attach a patch that does that for review.