tag edit dialog: fix popout link not always being bound.

Fix the popout link not being bound on the upload page when uploading
without the bookmarklet.

app/javascript/src/javascripts/posts.js.erb

@@ -35,7 +35,7 @@ Post.initialize_all = function() {
     }
   }
 
-  if ($("#image").length) {
+  if ($("#c-posts #a-show, #c-uploads #a-new").length) {
     this.initialize_edit_dialog();
   }