mesa: finish implementing glPrimitiveRestartNV() for display lists
If we try to build a display list with just a glPrimitiveRestartNV()
call, we'd crash because of a null GLvertexformat::PrimitiveRestartNV
pointer. This change fixes that case.
The previous patch fixed the case of calling glPrimitiveRestartNV()
inside a glBegin/End pair.
v2: minor clean-up in save_PrimitiveRestartNV(), per Charmaine.
Reviewed-by:
Charmaine Lee <charmainel@vmware.com>