pf: Remove support for 'scrub fragment crop|drop-ovl'

[kp]

Summary

The crop/drop-ovl fragment scrub modes are not very useful and likely to confuse
users into making poor choices.
It's also a fairly large amount of complex code, so just remove the support
altogether.

Users who have 'scrub fragment crop|drop-ovl' in their pf configuration will be
implicitly converted to 'scrub fragment reassemble'.

[eri]

It looks good in general, though I do not like automatic conversion in such case.
Just put in the commit as part of release notes and people need to be fully aware of the change.
Whoever used these options i am certain had their reasons so they should be aware of the change.

sys/netpfil/pf/pf_norm.c

434

Is this necessary to be removed?

935

Wouldn't be better to rewrite this completely to merged drop and bad together?

[kp]

sys/netpfil/pf/pf_norm.c

434

Yes, the fr_frags field no longer exists.