apply attach changes to demo

demo/client.ts

@@ -27,7 +27,6 @@ declare let window: IWindowWithTerminal;
 Terminal.applyAddon(fit);
 
 let term;
-let attachAddon: AttachAddon;
 let searchAddon: SearchAddon;
 let protocol;
 let socketURL;
@@ -90,8 +89,6 @@ function createTerminal(): void {
   // Load addons
   const typedTerm = term as TerminalType;
   typedTerm.loadAddon(new WebLinksAddon());
-  attachAddon = new AttachAddon();
-  typedTerm.loadAddon(attachAddon);
   searchAddon = new SearchAddon();
   typedTerm.loadAddon(searchAddon);
 
@@ -152,7 +149,7 @@ function createTerminal(): void {
 }
 
 function runRealTerminal(): void {
-  attachAddon.attach(socket);
+  term.loadAddon(new AttachAddon(socket));
   term._initialized = true;
 }