do not run discover parts if properties failed to complete

lib/App/Netdisco/Worker/Plugin/Discover/PortPower.pm

@@ -11,6 +11,7 @@ register_worker({ phase => 'main', driver => 'snmp' }, sub {
   my ($job, $workerconf) = @_;
 
   my $device = $job->device;
+  return unless $device->in_storage;
   my $snmp = App::Netdisco::Transport::SNMP->reader_for($device)
     or return Status->defer("discover failed: could not SNMP connect to $device");