workarounds: add plasma-discover with fix for #2173022

Just using a scratch build for now as my fix hasn't been reviewed
and may have dumb mistakes in it, but it does seem to fix the
openQA test at least.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

lib/utils.pm

@@ -480,7 +480,7 @@ sub setup_workaround_repo {
         "36" => [],
         "37" => [],
         "38" => [],
-        "39" => [],
+        "39" => ["97911079"],
     );
     # then we'll download each update for our release:
     my $advortasks = $workarounds{$version};