Fix iflib_encap() EFBIG handling bugs
- Don't give up if m_collapse() fails. Rather than giving up, try
m_defrag() immediately.
- Fix a leak where, if the NIC driver rejected the defrag'ed chain
as having too many segments, we would fail to free the chain.
Reviewed by: Matthew Macy <mmacy@mattmacy.io> (this version of patch)
Submitted by: Matthew Macy <mmacy@mattmacy.io> (early version of leak fix)