tdf#124730 an attempt to remove entry that isn't there

Change-Id: If382f0419c8ea0a3b99c85942c05ee1e5a627e76
Reviewed-on: https://gerrit.libreoffice.org/70796
Tested-by: Jenkins
Reviewed-by: Adolfo Jayme Barrientos <fitojb@ubuntu.com>

sfx2/source/dialog/mgetempl.cxx

@@ -281,7 +281,9 @@ void SfxManageStyleSheetPage::UpdateName_Impl( weld::ComboBox* pBox,
     {
         // it is the current entry, which name was modified
         const bool bSelect = pBox->get_active_text() == aBuf;
-        pBox->remove_text(aBuf);
+        int nOldIndex = pBox->find_text(aBuf);
+        if (nOldIndex != -1)
+            pBox->remove(nOldIndex);
         pBox->append_text(rNew);
 
         if (bSelect)