Fix crash in GetDeviceLocalAccountPolicies

It was crashing because there was no primary user so we got a nullptr
dereference when using GetPrimaryUser().

TBR=poromov@chromium.org

Bug: 928596, 875205
Change-Id: I47cd1e2b002bc37a2170fc5c355c1df205444197
Reviewed-on: https://chromium-review.googlesource.com/c/1454499
Reviewed-by: Ivan Ĺ andrk <isandrk@chromium.org>
Commit-Queue: Askar Aitzhan <askaraitzhan@google.com>
Cr-Commit-Position: refs/heads/master@{#629090}
1 file changed