rethink r1269 once again: instead of updating the entry group state in

rethink r1269 once again: instead of updating the entry group state in
EntryGroup::Commit() immediately (which would cause the state change callback
function to be called from the current stack frame which might be roblem for
some programs), do it asynchronously again, like in pre-r1269. However, modify
GetState() to always return the real state by asking the server if we have
doubt that our locally cached state is out-of-date.

git-svn-id: file:///home/lennart/svn/public/avahi/trunk@1271 941a03a8-eaeb-0310-b9a0-b1bbd8fe43fe