qemu-char: check optional fields using has_*

Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Reviewed-by: NLaszlo Ersek <lersek@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

qemu-char.c

@@ -3493,7 +3493,7 @@ static CharDriverState *qmp_chardev_open_file(ChardevFile *file, Error **errp)
 {
     HANDLE out;
 
-    if (file->in) {
+    if (file->has_in) {
         error_setg(errp, "input file not supported");
         return NULL;
     }
@@ -3544,7 +3544,7 @@ static CharDriverState *qmp_chardev_open_file(ChardevFile *file, Error **errp)
         return NULL;
     }
 
-    if (file->in) {
+    if (file->has_in) {
         flags = O_RDONLY;
         in = qmp_chardev_open_file_source(file->in, flags, errp);
         if (error_is_set(errp)) {