Add description to needs_update calculations

We're caching the data already. If we at this, it'll cause us to update
descriptions in github when they change.

Change-Id: I1941958cca6387bd17fd3dcfd3c519af8b355453
diff --git a/jeepyb/cmd/manage_projects.py b/jeepyb/cmd/manage_projects.py
index 7d85e95..603edea 100644
--- a/jeepyb/cmd/manage_projects.py
+++ b/jeepyb/cmd/manage_projects.py
@@ -261,6 +261,8 @@
         needs_update = True
     if cache.get('has_wiki', default_has_wiki) != has_wiki:
         needs_update = True
+    if cache.get('description') != description:
+        needs_update = True
     if not needs_update:
         return False