oracle template: restrict writeability in /proc and /sys

Note that since we don't drop CAP_SYS_ADMIN, root in the container can
remount proc or sys however they want to, however this at least improves
the default situation.

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>