termina: remove unused test image flags in termina_build_image

BUG=none
TEST=build_packages --board=tatl; build_image --board=tatl;
termina_build_image --image=chromiumos_test_image.bin --output=tatl;
termina_build_image -h shows correct flags;

Change-Id: I354335c7cbec5a24b483c5217ddc133fa15fed25
Reviewed-on: https://chromium-review.googlesource.com/1561352
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Trent Begin <tbegin@chromium.org>
Reviewed-by: Stephen Barber <smbarber@chromium.org>
Reviewed-by: Chirantan Ekbote <chirantan@chromium.org>
1 file changed