message: contrib: Add explicit port numbers for testnet seeds
  This is necessary now due to parsing change.
diff: # List of fixed seed nodes for testnet
  # Onion nodes
  -thfsmmn2jbitcoin.onion
  -it2pj4f7657g3rhi.onion
  -nkf5e6b7pl4jfd4a.onion
  -4zhkir2ofl7orfom.onion
  -t6xj6wilh4ytvcs7.onion
  -i6y6ivorwakd7nw3.onion
  -ubqj4rsu3nqtxmtp.onion
  +thfsmmn2jbitcoin.onion:18333
  +it2pj4f7657g3rhi.onion:18333
  +nkf5e6b7pl4jfd4a.onion:18333
  +4zhkir2ofl7orfom.onion:18333
  +t6xj6wilh4ytvcs7.onion:18333
  +i6y6ivorwakd7nw3.onion:18333
  +ubqj4rsu3nqtxmtp.onion:18333
  