Loopback pf_norm.c rev. 1.106 from OpenBSD:     fixup IP checksum when modifying IP header fields
Loopback pf_norm.c rev. 1.106 from OpenBSD:
    fixup IP checksum when modifying IP header fields

PR:		kern/93849
Obtained from:	OpenBSD
MFC after:	3 days

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase