Add -4 and -6 options to flashproxy-reg-http.
Add -4 and -6 options to flashproxy-reg-http.

Cf. b9784a46, which was the same for flashproxy-reg-email. This patch is
part of one by Jorge Couchet.
https://github.com/uyjco0/flashproxy/commit/2afd2fd53e20b3dfb5bd2605ce74ba60a746f899

glamrock/flashproxy,glamrock/flashproxy,infinity0/flashproxy,infinity0/flashproxy,arlolra/flashproxy,glamrock/flashproxy,infinity0/flashproxy,arlolra/flashproxy,glamrock/flashproxy,arlolra/flashproxy,infinity0/flashproxy,glamrock/flashproxy,arlolra/flashproxy,glamrock/flashproxy,arlolra/flashproxy,infinity0/flashproxy,arlolra/flashproxy,infinity0/flashproxy,arlolra/flashproxy