Fix Minijail's getopt string.
Fix Minijail's getopt string.

"-F" option does not exist.

BUG=None
TEST=security_Minijail0

Change-Id: I7463288d0555636d1c96373e61494082738111bd
Reviewed-on: https://gerrit.chromium.org/gerrit/28876
Tested-by: Jorge Lucangeli Obes <bc323d654c912a6c99763475eeb77a04da410a4a@chromium.org>
Reviewed-by: Kees Cook <50cb10d2be062154b17ab4d66a4eab34f1cf1c84@chromium.org>
Commit-Ready: Jorge Lucangeli Obes <bc323d654c912a6c99763475eeb77a04da410a4a@chromium.org>

omegaup/minijail,omegaup/minijail,omegaup/minijail,omegaup/minijail