[BUGFIX beta] Ensure that AttrNode's for value are rendered at least …

…once.

packages/ember-htmlbars/tests/attr_nodes/value_test.js

@@ -43,5 +43,17 @@ QUnit.test("string property is output", function() {
         'property is set true');
 });
 
+QUnit.test("blank property is output", function() {
+  view = EmberView.create({
+    context: { name: '' },
+    template: compile("<input value={{name}}>")
+  });
+  appendView(view);
+
+  equal(view.element.firstChild.tagName, 'INPUT', "input element is created");
+  equal(view.element.firstChild.value, "",
+        'property is set true');
+});
+
 // jscs:enable validateIndentation
 }

packages/ember-views/lib/attr_nodes/attr_node.js

@@ -25,6 +25,7 @@ AttrNode.prototype.init = function init(attrName, simpleAttrValue) {
   this.isDirty = true;
   this.isDestroying = false;
   this.lastValue = null;
+  this.hasRenderedInitially = false;
 
   subscribe(this.attrValue, this.rerender, this);
 };
@@ -52,14 +53,15 @@ AttrNode.prototype.render = function render(buffer) {
   }
 
   // If user is typing in a value we don't want to rerender and loose cursor position.
-  if (this.attrName === 'value' && this._morph.element.value === value) {
+  if (this.hasRenderedInitially && this.attrName === 'value' && this._morph.element.value === value) {
     this.lastValue = value;
     return;
   }
 
   if (this.lastValue !== null || value !== null) {
     this._morph.setContent(value);
     this.lastValue = value;
+    this.hasRenderedInitially = true;
   }
 };