x11/luit: Update MASTER_SITES

Add "/pub" which is the canonical path in FTP as site owner suggested
Add the HTTP master site as submitter suggested

PR: 258741
Reported by: bas@area536.com
MFH: 2021Q3

(cherry picked from commit 9abd1e471d91afabd00fd4a1f699e923faf7f69c)