LookupServer: Port to socket takeover

Author: https://github.com/bugaevc
Commit: https://github.com/SerenityOS/serenity/commit/ab98969403f
Pull-request: https://github.com/SerenityOS/serenity/pull/827

Base/etc/SystemServer.ini

@@ -11,6 +11,7 @@ KeepAlive=1
 User=anon
 
 [LookupServer]
+Socket=/tmp/portal/lookup
 Priority=low
 KeepAlive=1
 User=anon

Libraries/LibC/netdb.cpp

@@ -30,7 +30,7 @@ static int connect_to_lookup_server()
 
     sockaddr_un address;
     address.sun_family = AF_LOCAL;
-    strcpy(address.sun_path, "/tmp/.LookupServer-socket");
+    strcpy(address.sun_path, "/tmp/portal/lookup");
 
     int retries = 3;
     int rc = 0;

Servers/LookupServer/LookupServer.cpp

@@ -49,7 +49,7 @@ LookupServer::LookupServer()
             const_cast<CLocalSocket&>(*socket).on_ready_to_read = []{};
         };
     };
-    bool ok = m_local_server->listen("/tmp/.LookupServer-socket");
+    bool ok = m_local_server->take_over_from_system_server();
     ASSERT(ok);
 }