[#7059] Improve tarball status UX

* Don't say 'Generating' when we're not
* Fail quickly when we know snapshot isn't being built

Signed-off-by: Tim Van Steenburgh <tvansteenburgh@gmail.com>
diff --git a/Allura/allura/templates/repo/tarball.html b/Allura/allura/templates/repo/tarball.html
index 92b7af4..2338be1 100644
--- a/Allura/allura/templates/repo/tarball.html
+++ b/Allura/allura/templates/repo/tarball.html
@@ -53,8 +53,8 @@
             left: 10 // Left position relative to parent in px
         };
         var spinner = new Spinner(opts).spin($('#snapshot_status')[0]);
-        var delay = 500, elapsed = 0;
-        $('#snapshot_status h2.busy').show();
+        var delay = 500;
+        $('#snapshot_status h2.checking').show();
         function check_status() {
             $.get('{{commit.url()}}tarball_status?path={{path}}', function(data) {
                 if (data.status === 'complete') {
@@ -67,13 +67,14 @@
                 } else {
                     if (data.status === 'ready' || data.status === 'busy') {
                         // keep waiting
-                    } else if (data.status === 'error' || elapsed > 5000) {
+                        $('#snapshot_status h2').hide();
+                        $('#snapshot_status h2.busy').show();
+                    } else {
                         // something went wrong
                         spinner.stop();
                         $('#snapshot_status h2').hide();
                         $('#snapshot_status form').show();
                     }
-                    elapsed += delay;
                     if (delay < 60000){
                         delay = delay * 2;
                     }
@@ -90,6 +91,7 @@
 {% block content %}
 {% set path = request.params.get('path', '') %}
 <div id='snapshot_status'>
+    <h2 class="checking">Checking snapshot status...</h2>
     <h2 class="busy">Generating snapshot...</h2>
     <h2 class="complete">Your download will begin shortly, or use this <a href="{{c.app.repo.tarball_url(revision, path)}}">direct link</a>.</h2>
     <form action="tarball" method="post">