We need a+x rights on the path to the root of the jails
so we can use users other than root (like nobody)

This partly fixes jailed dnsmasq
Signed-off-by: Etienne CHAMPETIER <champetier.etienne@gmail.com>

Backport of r46466

git-svn-id: svn://svn.openwrt.org/openwrt/branches/chaos_calmer@46510 3c298f89-4303-0410-b956-a3cf2f4a3e73