We were a bit too enthusiastic when we copied libunbound and some other

We were a bit too enthusiastic when we copied libunbound and some other
helper functions from unbound(8).
Delete unused shared memory functions that the unbound(8) daemon uses
for statistics gathering. While here get rid of daemon.h which is
unused, too.
With this we can remove the hack in config.h to pretend we don't have
shmget to prevent linker errors which makes syncing with unbound(8)
easier.