Add `varnish_extra_flags` variable.

[feld]

Summary

Currently, if I want to add a single extra flag to varnishd_flags I need
to rebuild the whole thing:

${varnishd_flags:="-P ${varnishd_pidfile} -a ${varnishd_listen} \
  -T ${varnishd_admin} -b ${varnishd_backend} -s ${varnishd_storage} \
  -h ${varnishd_hash} -u ${varnishd_user} -g ${varnishd_group}"}

This commit adds a varnishd_extra_flags variable that I can use for these
kinds of minor tweaks (e.g., adding -p send_timeout=XXX).

[feld]

Thanks for the patch. We definitely want to make it easy for users to be able to pass any flag they want.

[jonathan]

Great: if things look ok to you, would you be the right person to commit the change (I'm not a ports committer)?

[feld]

Yes, I'll be the one comitting it.

I haven't done so yet as I recently inherited this port and haven't touched the rc script files yet. They need some changes to pass the devel/rclint tests to ensure they're following modern best practices. I've made the majority of the required changes, but was caught on one issue that doesn't have a workaround, so I'll just have to leave it as-is.

I'll be uploading the changes to this review momentarily.

[feld]

Bump PORTREVISION
Clean up rc scripts to pass rclint as much as possible

[feld]

Would you mind giving this diff a spin and letting me know if you run into any issues? I haven't been able to reproduce any so far.