microdroid_manager shuts down on failure

When payload verification fails, microdroid_manager triggers shutdown so
that VirtualizationService gets notified and then again forwards the
event to VM user apps.

Repro:
1. adb shell apex/com.android.compos/bin/composd_cmd \
   forced-compile-test
2. update compos apex (reboot)
3. run compos again

Bug: 204073443
Test: see above
Change-Id: Ide4d77f693e77a57eb15dd727eb50360abca6acb
diff --git a/microdroid_manager/src/main.rs b/microdroid_manager/src/main.rs
index a2fab07..f666294 100644
--- a/microdroid_manager/src/main.rs
+++ b/microdroid_manager/src/main.rs
@@ -69,7 +69,10 @@
 
 fn main() {
     if let Err(e) = try_main() {
-        error!("failed with {:?}", e);
+        error!("Failed with {:?}. Shutting down...", e);
+        if let Err(e) = system_properties::write("sys.powerctl", "shutdown") {
+            error!("failed to shutdown {:?}", e);
+        }
         std::process::exit(1);
     }
 }