empty_target_test: avoid segfault
empty_target_test: avoid segfault

Signed-off-by: Eugene Smirnov <a16d8468c5d1db13e92eb74ab4de95e1b7a8acf9@here.com>

advancedtelematic/aktualizr,advancedtelematic/aktualizr,advancedtelematic/aktualizr,advancedtelematic/aktualizr