give operators o,c some labels for translation

app/models/cost_query/operator.rb

@@ -1,6 +1,6 @@
 class CostQuery::Operator < Report::Operator
   # Operators from Redmine
-  new "c", :arity => 0 do
+  new "c", :arity => 0, :label => :label_closed do
     def modify(query, field, *values)
       raise "wrong field" if field.to_s.split('.').last != "status_id"
       query.where "(#{IssueStatus.table_name}.is_closed = #{quoted_true})"
@@ -8,7 +8,7 @@ class CostQuery::Operator < Report::Operator
     end
   end
 
-  new "o", :arity => 0 do
+  new "o", :arity => 0, :label => :label_open do
     def modify(query, field, *values)
       raise "wrong field" if field.to_s.split('.').last != "status_id"
       query.where "(#{IssueStatus.table_name}.is_closed = #{quoted_false})"