Make sure meteor shell options JSON is parsed separately.

Also don't ignore the `error` parameter passed to the readJSONFromStream
callback function.

Fixes #7312.

tools/shell-client.js

@@ -134,7 +134,7 @@ Cp.setUpSocket = function setUpSocket(sock, key) {
     sock.write(JSON.stringify({
       terminal: ! process.env.EMACS,
       key: key
-    }));
+    }) + "\n");
 
     process.stderr.write(shellBanner());
     process.stdin.pipe(sock);

tools/static-assets/server/shell-server.js

@@ -161,6 +161,12 @@ Sp.onConnection = function onConnection(socket) {
   readJSONFromStream(socket, function (error, options, replInputSocket) {
     clearTimeout(timeout);
 
+    if (error) {
+      socket = null;
+      console.error(error.stack);
+      return;
+    }
+
     if (options.key !== self.key) {
       if (socket) {
         socket.end(EXITING_MESSAGE + "\n");