Added property to control duration between migration attempts.

Bug: 140311307
Test: E2E completed successfully; migration completed successfully.
Change-Id: Ibef451e8e5a6b70b40ad92f369db2a808ec154a9
diff --git a/vendor/google/property_contexts b/vendor/google/property_contexts
index 660a10d..bc1cb01 100644
--- a/vendor/google/property_contexts
+++ b/vendor/google/property_contexts
@@ -52,6 +52,7 @@
 persist.vendor.faceauth.pose_bucket_stages          u:object_r:vendor_faceauth_prop:s0
 persist.vendor.faceauth.selection_tuning_frames     u:object_r:vendor_faceauth_prop:s0
 persist.vendor.faceauth.enable_migration            u:object_r:vendor_faceauth_prop:s0
+persist.vendor.faceauth.migration_attempt_period    u:object_r:vendor_faceauth_prop:s0
 
 persist.vendor.shutdown.                        u:object_r:vendor_shutdown_prop:s0