odhcpd: use hybrid management mode by default

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@39313 3c298f89-4303-0410-b956-a3cf2f4a3e73
odhcpd: fix logspam

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@39314 3c298f89-4303-0410-b956-a3cf2f4a3e73