http: always use any proxy auth method available

We set CURLOPT_PROXYAUTH to use the most secure authentication
method available only when the user has set configuration variables
to specify a proxy.  However, libcurl also supports specifying a
proxy through environment variables.  In that case libcurl defaults
to only using the Basic proxy authentication method, because we do
not use CURLOPT_PROXYAUTH.

Set CURLOPT_PROXYAUTH to always use the most secure authentication
method available, even when there is no git configuration telling us
to use a proxy. This allows the user to use environment variables to
configure a proxy that requires an authentication method different
from Basic.

Signed-off-by: Enrique A. Tobis <etobis@twosigma.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: etobis

http.c

@@ -406,10 +406,10 @@ static CURL *get_curl_handle(void)
 
 	if (curl_http_proxy) {
 		curl_easy_setopt(result, CURLOPT_PROXY, curl_http_proxy);
+	}
 #if LIBCURL_VERSION_NUM >= 0x070a07
-		curl_easy_setopt(result, CURLOPT_PROXYAUTH, CURLAUTH_ANY);
+	curl_easy_setopt(result, CURLOPT_PROXYAUTH, CURLAUTH_ANY);
 #endif
-	}
 
 	set_curl_keepalive(result);