Nis Jorgensen filed bug report #1338648

(http://curl.haxx.se/bug/view.cgi?id=1338648) which really is more of a
feature request, but anyway. It pointed out that --max-redirs did not allow
it to be set to 0, which then would return an error code on the first
Location: found. Based on Nis' patch, now libcurl supports CURLOPT_MAXREDIRS
set to 0, or -1 for infinity. Added test case 274 to verify.