kirkwood: add *plugs to uci-defaults

Set defaults health led to a timer heartbeet (200/800)
and populate network for:

- GuruplugServerPlus
- SheevaPlug
- SheevaPlug with eSATA

Signed-off-by: Gerald Kerma <dreagle@doukki.net>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@43752 3c298f89-4303-0410-b956-a3cf2f4a3e73