show something for the link name if there is no link body

Change-Id: I9a445bed6072a48c2eca67ee403218e749ff3feb
Reviewed-on: https://gerrit.libreoffice.org/47800Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

cui/source/dialogs/linkdlg.cxx

@@ -628,7 +628,7 @@ void SvBaseLinksDlg::InsertEntry( const SvBaseLink& rLink, sal_uLong nPos, bool
 
     if( aFileName.getLength() > aTxt.getLength() )
         aTxt = aFileName;
-    else if( aTxt.indexOf( aFileName, aTxt.getLength() - aFileName.getLength() ) == -1 )
+    else if (!aFileName.isEmpty() && aTxt.indexOf(aFileName, aTxt.getLength() - aFileName.getLength()) == -1)
         // filename not in string
         aTxt = aFileName;