- allowed the case of rt_refcnt < 0 in rt_draincache(), just following the   convention - removed each rttimer entry in rt_draincache() itself.
- allowed the case of rt_refcnt < 0 in rt_draincache(), just following the
  convention
- removed each rttimer entry in rt_draincache() itself.

MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame