remove unused and un-freed GError

docs say passing null is allowed

Author: chearon

src/Image.cc

@@ -1471,9 +1471,8 @@ Image::loadSVGFromBuffer(uint8_t *buf, unsigned len) {
  _is_svg = true;
 
  cairo_status_t status;
- GError *gerr = NULL;
 
- if (NULL == (_rsvg = rsvg_handle_new_from_data(buf, len, &gerr))) {
+ if (NULL == (_rsvg = rsvg_handle_new_from_data(buf, len, nullptr))) {
  return CAIRO_STATUS_READ_ERROR;
  }