table: rename cs::iterator to cs::Table::const_iterator

refs #4914

Change-Id: I0d81a0983c6bbf8ad2bdf78eec4f37ac73ec3d2d
diff --git a/daemon/table/cs-entry.hpp b/daemon/table/cs-entry.hpp
index eadb9f6..5dd931d 100644
--- a/daemon/table/cs-entry.hpp
+++ b/daemon/table/cs-entry.hpp
@@ -115,7 +115,11 @@
  */
 using Table = std::set<Entry, std::less<>>;
 
-using iterator = Table::const_iterator;
+inline bool
+operator<(Table::const_iterator lhs, Table::const_iterator rhs)
+{
+  return *lhs < *rhs;
+}
 
 } // namespace cs
 } // namespace nfd