misleading comment: not every sheet is examined

In fact, if there are no sheet-local names defined, then the loop
will not even be entered. Only the sheets that actually contain
the desired item will be iterated through.

Change-Id: I1fa94d8b9190f43b2896a002acdec18397225395
Reviewed-on: https://gerrit.libreoffice.org/54742Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Andras Timar <andras.timar@collabora.com>

sc/source/filter/excel/xename.cxx

@@ -645,7 +645,7 @@ void XclExpNameManagerImpl::CreateUserNames()
         if (!FindNamedExpIndex(SCTAB_GLOBAL, itr->second->GetIndex()))
             CreateName(SCTAB_GLOBAL, *itr->second);
     }
-    //look at every sheet for local range names
+    //look at sheets containing local range names
     ScRangeName::TabNameCopyMap rLocalNames;
     GetDoc().GetAllTabRangeNames(rLocalNames);
     ScRangeName::TabNameCopyMap::iterator tabIt = rLocalNames.begin(), tabItEnd = rLocalNames.end();