[Bug 1096296] man page inaccuracy about --sig-proxy and --tty

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=1096296

--- Comment #5 from Matthew Heon  ---
Upstream is looking at the pull request. It still needs some work before I
would say it is done and ready for inclusion in RHEL builds - need comments on
how to proceed with a potentially significant change.