Allow -onlynet=onion to be used

Just an alias for onlynet=tor, but matches the new name
of the proxy option -onion= better.

src/init.cpp

@@ -248,7 +248,7 @@ std::string HelpMessage(HelpMessageMode mode)
     strUsage += "  -maxreceivebuffer=<n>  " + _("Maximum per-connection receive buffer, <n>*1000 bytes (default: 5000)") + "\n";
     strUsage += "  -maxsendbuffer=<n>     " + _("Maximum per-connection send buffer, <n>*1000 bytes (default: 1000)") + "\n";
     strUsage += "  -onion=<ip:port>       " + _("Use separate SOCKS5 proxy to reach peers via Tor hidden services (default: -proxy)") + "\n";
-    strUsage += "  -onlynet=<net>         " + _("Only connect to nodes in network <net> (IPv4, IPv6 or Tor)") + "\n";
+    strUsage += "  -onlynet=<net>         " + _("Only connect to nodes in network <net> (IPv4, IPv6 or Onion)") + "\n";
     strUsage += "  -permitbaremultisig    " + _("Relay non-P2SH multisig (default: 1)") + "\n";
     strUsage += "  -port=<port>           " + _("Listen for connections on <port> (default: 8333 or testnet: 18333)") + "\n";
     strUsage += "  -proxy=<ip:port>       " + _("Connect through SOCKS5 proxy") + "\n";

src/netbase.cpp

@@ -47,7 +47,7 @@ enum Network ParseNetwork(std::string net) {
     boost::to_lower(net);
     if (net == "ipv4") return NET_IPV4;
     if (net == "ipv6") return NET_IPV6;
-    if (net == "tor")  return NET_TOR;
+    if (net == "tor" || net == "onion")  return NET_TOR;
     return NET_UNROUTABLE;
 }