Updated curl adapter file handling to prevent warnings in php >=5.5.0

library/Solarium/Core/Client/Adapter/Curl.php

@@ -179,8 +179,14 @@ class Curl extends Configurable implements AdapterInterface
 
         if ($method == Request::METHOD_POST) {
             curl_setopt($handler, CURLOPT_POST, true);
+
             if ($request->getFileUpload()) {
-                curl_setopt($handler, CURLOPT_POSTFIELDS, array('content' => '@'.$request->getFileUpload()));
+                if (version_compare(PHP_VERSION, '5.5.0') >= 0) {
+                    $curlFile = curl_file_create($request->getFileUpload());
+                    curl_setopt($handler, CURLOPT_POSTFIELDS, array('content', $curlFile));
+                } else {
+                    curl_setopt($handler, CURLOPT_POSTFIELDS, array('content' => '@'.$request->getFileUpload()));
+                }
             } else {
                 curl_setopt($handler, CURLOPT_POSTFIELDS, $request->getRawData());
             }