pfctl: print_rule: rename opts -> ropts

no binary change
1/2 from Lawrence Teo <lteo at devio dot us>
ok sthen dlg myself and gcc

Obtained from: OpenBSD, henning <henning@openbsd.org>, 6992ade79a
Sponsored by: Rubicon Communications, LLC ("Netgate")
Differential Revision: https://reviews.freebsd.org/D47800