crash because iterator position wasn't changed in stl conversion

regression from e0284f4bba59912e1c49cb36936e041e891a5833

Here's the original code using the pre stl iterators.

if( !pPara && nDepth > 0 &&  rSet.GetItemState( EE_PARA_NUMBULLET ) == SFX_ITEM_ON &&
    pOutliner->GetDepth( (sal_uInt16) pOutliner->GetAbsPos( (Paragraph*) pList->First() ) ) > 0 )
	pPara = pOutliner->GetParagraph( 0 );  // Put NumBulletItem in outline level 1

Hidden in there is a pList->First() which only gets called if the prior
conditions are true.  pList->First() resets the index of the internal pList
iterator position of pList to 0 i.e. the next call to pList->Prev will now return 0.

The equivalent in the post-stl-conversion code is to jump the reverse_iterator
iter to the last position in the reverse view.

Create a level 10 entry in master view, select level 10, and use the bullets
and numbering dropdown from the side panel to see this crash

Change-Id: I52c22ea52020feb0fb75924f63ebe225be462071