dhcpdns: add comments to some possible points of failure. pull out IP database initialisation from object constructor to perhaps reconstruct the db in the future.
dhcpdns: add comments to some possible points of failure. pull out IP database initialisation from object constructor to perhaps reconstruct the db in the future.

git-svn-id: bf82309ee31681273af20a825c7064ea7c5af838@1309063 13f79535-47bb-0310-9956-ffa450edef68

stroucki/tashi,stroucki/tashi,stroucki/tashi