tree c0bce55730b7d98f85042ec4bf65607c5bcd8569
parent 5ed02df6e7cafa95ce20a3c0e4fdccd0f50e7faf
author Elliott Hughes <enh@google.com> 1591391175 -0700
committer Luca Weiss <luca.weiss@fairphone.com> 1655898257 +0200

Fix `fastboot flash-all` on Nexus 7.

The Nexus 7 bootloader just returns the empty string for unknown
variables, which confused the new snapshot code.

Bug: https://issuetracker.google.com/158232468
Test: no Nexus 7 available during covid-19 :-(
Change-Id: I35ff8889b27944e8b7426eca4f513d9fa562c6d4
(cherry picked from commit 6a7ff5811da1f4c2be28f313c5ab058afac74a60)