- add config check for given volumes

lib/SLUB/LZA/TA.pm

@@ -67,6 +67,9 @@ HINT
     use warnings;
     # option overrides config
     $config{elasticsearch_protocol} = $config{http_only} ? 'http' : 'https';
+    foreach my $volume (@{ $SLUB::LZA::TA::config{permanent_volume} }) {
+        if (! -d "$volume") {$self->usage_error("given volume '$volume', does not exist or readable, $!");}
+    }
     return 1;
 }