coverity#704902 Dereference after null check

Change-Id: Ib0c590f452b0fd2df042a200015c935b46070fde

sw/source/core/layout/fly.cxx

@@ -919,6 +919,8 @@ void SwFlyFrm::_UpdateAttr( const SfxPoolItem *pOld, const SfxPoolItem *pNew,
                 getRootFrm()->InvalidateBrowseWidth();
             SwRect aNew( GetObjRectWithSpaces() );
             SwRect aOld( maFrm );
+            if (pNew)
+            {
                 if ( RES_UL_SPACE == nWhich )
                 {
                     const SvxULSpaceItem &rUL = *(SvxULSpaceItem*)pNew;
@@ -931,6 +933,7 @@ void SwFlyFrm::_UpdateAttr( const SfxPoolItem *pOld, const SfxPoolItem *pNew,
                     aOld.Left  ( std::max( aOld.Left() - long(rLR.GetLeft()), 0L ) );
                     aOld.SSize().Width() += rLR.GetRight();
                 }
+            }
             aNew.Union( aOld );
             NotifyBackground( FindPageFrm(), aNew, PREP_CLEAR );
         }