svm: Fixed error code comparison in test npt_rsvd_pfwalk

According to the AMD64 spec Bit 3 (RSV) in exitinfo1 should be set
to 1 if reserved bits were set in the corresponding nested page
table entry. Exitinfo1 should be checking against error code
0x20000000eULL not 0x200000006ULL.

Signed-off-by: Cathy Avery <cavery@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>