packet-openflow_v1.c: Rename "Padding" fields & filter-names to be consistent with those in packet-openflow_v5.c

Change-Id: Idd78b49cad86db6f63b4f14edbf4d954120665e3
Also: remove some commented-out "Padding" hf[] entries.
Reviewed-on: https://code.wireshark.org/review/4257
Reviewed-by: Bill Meier <wmeier@newsguy.com>