MFH: r506777

archivers/arj: Unbreak upgrading debian patchset

Version 17 of debian patches is not available anymore. Upgrade it to use
version 21 and fix the build

PR: 239233
Reported by: Darin Luckie <darin@technotic.ca>
Sponsored by: Rubicon Communications, LLC (Netgate)
Approved by: ports-secteam (miwi)