Merge pull request #1817 in SNORT/snort3 from ~MIALTIZE/snort3:checksum_offsets to...

Merge pull request #1817 in SNORT/snort3 from ~MIALTIZE/snort3:checksum_offsets to master

Squashed commit of the following:

commit 344219c01b7e1e8fe5912018441d29fd8aaf6b44
Author: Michael Altizer <mialtize@cisco.com>
Date:   Thu Oct 24 12:50:23 2019 -0400

    codecs: Relax requirement for DAQ packet decode data offsets when bypassing checksums

    Only perform the offset sanity checking during checksum bypass
    evaluation if the offset has been explicitly set in the packet decode
    data.  Otherwise, assume that the relevant checksum validation applies
    to the current instance of the protocol.