curlHeaderCallback() should join headers if no colon found

Working on #278425-55: Using basename() is not locale safe

Details http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2

   protected function curlHeaderCallback($curlHandler, $header) {
-    $this->headers[] = $header;
+    // Headers could be splited on chunks so prepending last header line if
+    // current header has no colon (":"). Additional details could be found
+    // in rfc2616 http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2
+    if (strpos($header, ':') === FALSE) {
+      $this->headers[] = array_pop($this->headers) . $header;
+    }
+    else {
+      $this->headers[] = $header;
+    }