CurlHttpRequest: Check library version, not CURLOPT_REDIR_PROTOCOLS

This works around <https://github.com/facebook/hhvm/issues/3702>.
We don't actually use the constant, so checking the library version
should suffice.

Bug: 70570
Change-Id: I732d8f7eb2908bae10100594f693cf7a63f8b5b1