Update rpc_server.js

Avoid unexpected type coercion

Author: BrandonShutter

javascript-nodejs/src/rpc_server.js

@@ -26,7 +26,7 @@ amqp.connect('amqp://localhost', function(err, conn) {
 });
 
 function fibonacci(n) {
-  if (n == 0 || n == 1)
+  if (n === 0 || n === 1)
     return n;
   else
     return fibonacci(n - 1) + fibonacci(n - 2);