capabilities: correct the <<-operator width everwhere
capabilities: correct the <<-operator width everwhere

The <<-operator here needs to always be 64bit, so use a variable instead
of trying to pick the right bit width, which will be arch-sensitive.

BUG=chromium-os:38643
TEST=link and daisy build, both pass security_Minijail

Change-Id: Ifab3037bf74f09256924993a8e91315b4b0ac998
Signed-off-by: Kees Cook <50cb10d2be062154b17ab4d66a4eab34f1cf1c84@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/42806
Reviewed-by: Jorge Lucangeli Obes <bc323d654c912a6c99763475eeb77a04da410a4a@chromium.org>

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