LinuxServer Changes:
Install unrar from linuxserver repo.
mylar3 Changes:
search: fix call of sfs.checker when using DDL RSS search
Specifically, we would see a traceback if there were issues for a search
in the RSS feed database: this fixes that codepath to pass the correct
values to checker().
(This must be the change I should have made instead of that other change
we ended up undoing.)