[nsp] PXF crashes w/CEF enabled

[Brian Wallingford]

Running 12.2(7b), and have tried 12.2(x)T revs on VXRs w/NSE-1.  Without
exception, enabling CEF results in immediate pxf crashes (also on
reload).  CEF performs as expected (ahem, grin :), with significant cpu
time savings, barring any sudden connected route changes, but it would be
awfully nice to finally realize some benefit from pxf.

Any recommendation for an ios rev that performs reliably (no big bells &
whistles needed aside from CEF/CAR) w/pxf would be appreciated.

The boxes in question only have 2 or 3 pa-h's and pa-fe's apiece,
elementary bgp and ospf configs, no more than a few hundred pvc's, and
moderate (around 700 lines) acls.

cheers,
brian