Remove http.authAny

Remove http.authAny

Back when the feature to use different HTTP authentication methods was
originally written, it needed an extra HTTP request for everything when
the feature was in effect, because we didn't reuse curl sessions.

However, b8ac923 (Add an option for using any HTTP authentication scheme,
not only basic, 2009-11-27) builds on top of an updated codebase that does
reuse curl sessions; there is no need to manually avoid the extra overhead
by making this configurable anymore.

Acked-by: Martin Storsjo <martin@martin.st>
Acked-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>