fix(ngForm): don't block submit when method=dialog

When a form's method is set to "dialog" it does not post to a server but
instead closes the nearest parent <dialog> element. An action is not required.

Author: dpogue

src/ng/directive/form.js

@@ -485,7 +485,7 @@ var formDirectiveFactory = function(isNgForm) {
             var controller = ctrls[0];
 
             // if `action` attr is not present on the form, prevent the default action (submission)
-            if (!('action' in attr)) {
+            if (!('action' in attr) && attr['method'] !== 'dialog') {
               // we can't use jq events because if a form is destroyed during submission the default
               // action is not prevented. see #1238
               //