Npcap 1.81 clears high-order bit of 802.1p priority when injecting packets with 802.1q frame header

[dmiller-nmap]

The UserPriority field of the VLAN tag header was being extracted with the bitmask 0x70, selecting the 2nd through 4th bits, instead of 0xe0, selecting the 1st through 3rd bits. The resulting value is right-shifted 5 bits, so the effect was to clear the high-order bit so a priority of 7 became 3, 5 became 1, etc.

This issue was discovered by a Npcap OEM licensee and was fixed in c267418.