libsnapshot: Fix intermittent test failure due to missing null check.

Bug: 152547190
Test: vts_snapshot_test
Change-Id: If7adc4fba61325e52d6268531ce0a15b00c0a380
(cherry picked from commit 533b2b62965a6ce3509b07fefc178232547fe58d)
Merged-In: If7adc4fba61325e52d6268531ce0a15b00c0a380
1 file changed