packet-openflow_v1.c: Fix a bug in dissection of openflow_features_reply_v1

Fixes Bug #10493

Change-Id: Ia330a7b087ea184865fc437d77ee6ca57b1f2e44
Reviewed-on: https://code.wireshark.org/review/4256
Reviewed-by: Bill Meier <wmeier@newsguy.com>