http-fetch: Disable use of curl multi support for libcurl < 7.16.

curl_multi_remove_handle() is broken in libcurl < 7.16, in that it
doesn't correctly update the active handles count when a request is
aborted. This causes the transfer to hang forever waiting for the
handle count to become less than the number of active requests.
Signed-off-by: NAlexandre Julliard <julliard@winehq.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

http.h

@@ -6,7 +6,7 @@
 #include <curl/curl.h>
 #include <curl/easy.h>
 
-#if LIBCURL_VERSION_NUM >= 0x070908
+#if LIBCURL_VERSION_NUM >= 0x071000
 #define USE_CURL_MULTI
 #define DEFAULT_MAX_REQUESTS 5
 #endif