Output more detailed error information in sysvol_test
Output more detailed error information in sysvol_test

(cherry picked from commit 00435643bad9ce85a5a07fc0b20c3ab9fb3f097a)

uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend