Log a message if there is no escrow data for RoR

Bug: 181957098
Test: reboot, check the message is logged
Change-Id: If531931f1da106dd553e44d82bc595eaf875b195

services/core/java/com/android/server/locksettings/RebootEscrowManager.java

@@ -251,6 +251,8 @@ class RebootEscrowManager {
         }
 
         if (rebootEscrowUsers.isEmpty()) {
+            Slog.i(TAG, "No reboot escrow data found for users,"
+                    + " skipping loading escrow data");
             return;
         }