Revert "Keep the native terminal active when enabling gfxterm"

This can cause an issue where GRUB is trying to display both a text and graphical menu on the display at the same time, resulting in a flickering effect when e.g. scrolling quickly through a menu (LP: #1752767).

Revert for now while we look for a better solution for the original issue.

This reverts commit 52ef7b23f528ce844716661d586497a177e80d5b.

---
 util/grub.d/00_header.in | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 8d46fc973..93a90233e 100644
@@ -221,7 +221,7 @@ case x${GRUB_TERMINAL_OUTPUT} in
   ;;
   x*)
     cat << EOF
-terminal_output --append ${GRUB_TERMINAL_OUTPUT}
+terminal_output ${GRUB_TERMINAL_OUTPUT}
 EOF
   ;;
 esac

2.16.2

Reverted. Please CC me next time.

Daniel