NetDB: Skip LS verifies when shutting down
remove unneeded null check
NetDB: Iterative search improvements
- Pass DSRM hashes through IMD to ILJ for client tunnels too
- Query unknown DRSM hashes in ILJ without looking up
  when using client tunnels; look up after querying
  when using expl. tunnels to speed things up
- Don't look up banlisted hashes
- Check 'from' hash in DSRM against list of peers sent to
- Don't query an unknown peer through a zero-hop OB tunnel
- Log tweaks
Extend expiration of returned message in IMD
merge of '0c93d925b9ac38f2475b39aa2b80eaa1454214d6'
     and '97ec023f8ba85ebdabe5ee0bd3f9e107710f170f'