zram-swap: fix dependencies

swapon/swapoff are no longer provided by swap-utils; they are provided
by block-mount instead.

Signed-off-by: Nathan Hintz <nlhintz@hotmail.com>


git-svn-id: svn://svn.openwrt.org/openwrt/trunk@38795 3c298f89-4303-0410-b956-a3cf2f4a3e73