Fix issue since there was no defaulot state in IssuableFinder

Signed-off-by: Rémy Coutable <remy@rymai.me>

app/finders/issuable_finder.rb

@@ -201,7 +201,7 @@ class IssuableFinder
     when 'opened'
       items.opened
     else
-      raise 'You must specify default state'
+      items
     end
   end