dockerfiles/cleanup_and_update: remove force opt

This change removes the '-f' option from the
cleanup_and_update dockerfiles script in order
to prevent aggressive removal of in-development
docker images

Signed-off-by: Kelley Spoon <kelley.spoon@linaro.org>
Change-Id: Icf6778303081565eb2e99ec84c2eb695b14b9021
1 file changed