worker: keep output directory in /var/cache

Let's keep this on the same filesystem as the osbuild store, and
in particular stay away from /var/tmp and its scary semantics.

We are not aware of any issues caused by /var/tmp, but getting
rid of it means we don't have to think about that when debugging,
if nothing else.

Signed-off-by: Tom Gundersen <teg@jklm.no>

cmd/osbuild-worker/main.go

@@ -117,6 +117,8 @@ func main() {
 		log.Fatal("CACHE_DIRECTORY is not set. Is the service file missing CacheDirectory=?")
 	}
 	store := path.Join(cacheDirectory, "osbuild-store")
+	output := path.Join(cacheDirectory, "output")
+	_ = os.Mkdir(output, os.ModeDir)
 
 	kojiServers := make(map[string]koji.GSSAPICredentials)
 	for server, creds := range config.KojiServers {
@@ -152,10 +154,12 @@ func main() {
 	jobImpls := map[string]JobImplementation{
 		"osbuild": &OSBuildJobImpl{
 			Store:       store,
+			Output:      output,
 			KojiServers: kojiServers,
 		},
 		"osbuild-koji": &OSBuildKojiJobImpl{
 			Store:       store,
+			Output:      output,
 			KojiServers: kojiServers,
 		},
 		"koji-init": &KojiInitJobImpl{