jpeg handler: log error message on fatal error

Original libjpeg's handler has output_message call.

As Qt doesn't have it, it logs non-fatal error, but skips the fatal ones
which are likely more important to be logged than the non-fatal ones.

Pick-to: 6.5
Change-Id: Iebb94db4d56705322e7569445d240ca4a7ed8f4a
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>

src/plugins/imageformats/jpeg/qjpeghandler.cpp

@@ -49,6 +49,7 @@ extern "C" {
 
 static void my_error_exit (j_common_ptr cinfo)
 {
+    (*cinfo->err->output_message)(cinfo);
     my_error_mgr* myerr = (my_error_mgr*) cinfo->err;
     longjmp(myerr->setjmp_buffer, 1);
 }