Merge branch 'ab/http-drop-old-curl'

Support for ancient versions of cURL library (pre 7.19.4) has been dropped. * ab/http-drop-old-curl: http: rename CURLOPT_FILE to CURLOPT_WRITEDATA http: drop support for curl < 7.19.3 and < 7.17.0 (again) http: drop support for curl < 7.19.4 http: drop support for curl < 7.16.0 http: drop support for curl < 7.11.1