The packet encapsulation is in pkt_encap, not rec_type.

rec_type is the type of record (which isn't necessarily a packet; future
work on libwiretap will let it return non-packet data); if it's a packet
(REC_TYPE_PACKET), then pkt_encap contains the "link-layer"
encapsulation for the packet (in quotes because it may contain metadata
not transmitted over the network).

Change-Id: I6f32b02f4466df6d7b07dbdc9d77e881830ac749
Reviewed-on: https://code.wireshark.org/review/5645
Reviewed-by: Guy Harris <guy@alum.mit.edu>