luci-mod-system: drop not used setInitAction ubus luci permission

Drop not used setInitAction ubus luci method permission from
luci-mod-system-uhttpd and luci-mod-system-ssh. They are not used in the
related js files and should be removed as the related js doesn't
use/require them.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>