gpgconf: correct capitalization of "Tor"

* tools/gpgconf-comp.cb (gc_options_dirmngr): correct capitalization
of Tor.

https://www.torproject.org/docs/faq.html.en#WhyCalledTor says:

Note: even though it originally came from an acronym, Tor is not
spelled "TOR". Only the first letter is capitalized. In fact, we can
usually spot people who haven't read any of our website (and have
instead learned everything they know about Tor from news articles) by
the fact that they spell it wrong.

• Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>