fix(ipv4): More fragments flags was incorrectly reported as Evil (flags were reverded)
fix(ipv4): More fragments flags was incorrectly reported as Evil (flags
were reverded)

The flags are in order, from high order to low order:
* bit 0: Reserved; must be zero.
* bit 1: Don't Fragment (DF)
* bit 2: More Fragments (MF)

Also added some more commenting to the Evil flag.

xuzhaokui/gopacket,scroot/gopacket,lokikiller/gopacket,chapayGhub/gopacket,urso/gopacket,wheelcomplex/gopacket,1d4Nf6/gopacket,dazer-chen/gopacket,dazer-chen/gopacket,dutchcoders/gopacket,lokikiller/gopacket,aeppert/gopacket,levigross/gopacket,chapayGhub/gopacket,packetb-old/gopacket,LrsK/gopacket,packetbeat/gopacket,clarktrimble/gopacket,ross-williams/gopacket,UIKit0/gopacket-1,levigross/gopacket,zerklabs/gopacket,google/gopacket,google/gopacket,josephcopenhaver/gopacket,LrsK/gopacket,rouzier/gopacket,aeppert/gopacket,urso/gopacket,ross-williams/gopacket,ccordes-snaproute/gopacket,scroot/gopacket,breml/gopacket,vtolstov/gopacket,scroot/gopacket,wheelcomplex/gopacket,ross-williams/gopacket,xuzhaokui/gopacket,chapayGhub/gopacket,wheelcomplex/gopacket,UIKit0/gopacket-1,aeppert/gopacket,packetb-old/gopacket,rouzier/gopacket,nhooyr/gopacket,zerklabs/gopacket,UIKit0/gopacket-1,skyportsystems/gopacket,rouzier/gopacket,levigross/gopacket,dazer-chen/gopacket,xuzhaokui/gopacket,nhooyr/gopacket,1d4Nf6/gopacket,josephcopenhaver/gopacket,adriantam/gopacket,hkwi/gopacket,packetbeat/gopacket,hkwi/gopacket,zerklabs/gopacket,google/gopacket,dutchcoders/gopacket,vtolstov/gopacket,josephcopenhaver/gopacket,packetbeat/gopacket,packetbeat/gopacket,ccordes-snaproute/gopacket,lokikiller/gopacket,nhooyr/gopacket,skyportsystems/gopacket,adriantam/gopacket,ccordes-snaproute/gopacket,clarktrimble/gopacket,LrsK/gopacket,breml/gopacket,clarktrimble/gopacket,packetb-old/gopacket,packetb-old/gopacket,skyportsystems/gopacket,breml/gopacket,dutchcoders/gopacket,urso/gopacket,adriantam/gopacket,hkwi/gopacket,vtolstov/gopacket,1d4Nf6/gopacket