LibIPC: Close the socket and die when the peer is closed

This will close the socket when the recv() returns 0 indicating that
the peer has shutdown, and when there are no pending bytes to be
processed.

Userland/Libraries/LibIPC/Connection.h

@@ -196,7 +196,7 @@ protected:
             }
             if (nread == 0) {
                 if (bytes.is_empty()) {
-                    deferred_invoke([this](auto&) { die(); });
+                    deferred_invoke([this](auto&) { shutdown(); });
                 }
                 return false;
             }