Fix 500 error on page with submodules

app/views/projects/tree/_submodule_item.html.haml

-- url = submodule_item.url(@ref) rescue ''
-- name = submodule_item.basename
-- return '' unless url
-%tr{ class: "tree-item", url: url }
+%tr{ class: "tree-item" }
   %td.tree-item-file-name
     = image_tag "submodule.png"
-    %span= truncate(name, length: 40)
+    %span
+      = link_to truncate(submodule_item.name, length: 40), '#'
+    @
+    %span.monospace #{submodule_item.id[0..10]}
+  %td
+  %td
   %td
-    %code= submodule_item.id[0..10]
-  %td{ colspan: 2 }
-    = link_to truncate(url, length: 40), url