protect against missing Modifiers

Change-Id: I226f67c6c49bfcbc1fa0ef40fc9f7d5548fa043b
(cherry picked from commit 6c59adca)
Reviewed-on: https://gerrit.libreoffice.org/20510Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

lotuswordpro/source/filter/lwppara1.cxx

@@ -237,7 +237,7 @@ void LwpPara::GetParaNumber(sal_uInt16 nPosition, ParaNumbering* pParaNumbering)
                         {
                             if (
                                  (pFrib->GetNext() && pFrib->GetNext()->GetType() == FRIB_TAG_TEXT) ||
-                                 (pFrib->GetModifiers()->aTxtAttrOverride.GetHideLevels() == nHideLevels)
+                                 (pFrib->GetModifiers() && pFrib->GetModifiers()->aTxtAttrOverride.GetHideLevels() == nHideLevels)
                                )
                             {
                                 pParaNumbering->pSuffix = static_cast<LwpFribText*>(pFrib);