Handle unbranded Cockpit login screen, record soft failure

There's a bug in current Modular Server which results in Cockpit
having an unbranded login screen, let's handle this but record
it as a soft failure.

lib/utils.pm

@@ -302,6 +302,8 @@ sub start_cockpit {
     # run firefox directly in X as root. never do this, kids!
     type_string "startx /usr/bin/firefox -width 1024 -height 768 http://localhost:9090\n";
     assert_screen "cockpit_login";
+    # this happened on early Modular Server composes...
+    record_soft_failure "Unbranded Cockpit" if (match_has_tag "cockpit_login_unbranded");
     wait_still_screen 5;
     if ($login) {
         type_safely "root";

needles/cockpit/login-unbranded-20171107.json

@@ -0,0 +1,16 @@
+{
+  "area": [
+    {
+      "xpos": 893,
+      "type": "match",
+      "ypos": 131,
+      "height": 61,
+      "width": 60
+    }
+  ],
+  "properties": [],
+  "tags": [
+    "cockpit_login",
+    "cockpit_login_unbranded"
+  ]
+}