..and replace with debug header if multimap is used.

As seen in include/svx/SmartTagMgr.hxx

Change-Id: If239cd6e9471f74f3035c659077ed7515a9df473
Reviewed-on: https://gerrit.libreoffice.org/73367
Tested-by: Jenkins
Reviewed-by: Michael Stahl <Michael.Stahl@cib.de>