Update the vpopmail port to version 5.4.26 with a lot of changes and fixes:
- add the WITH_SPAMFOLDER knob from Alex Dupre's PR;
- fix lots of bugs in the new vlist code;
- fix a couple of bugs in MySQL's "valias -n" implementation;
- actually implement "valias -n" for PostgreSQL;
- fix a couple of directory descriptor leaks and other buglets.
PR: 117321 (the WITH_SPAMFOLDER knob)
Submitted by: ale