Log details if payload exits via signal

Bug: 200650431
Test: Crash compsvc, see message in log
Change-Id: I31e1ffc884378636d55a139118d4bd46d7d68865
diff --git a/microdroid_manager/src/main.rs b/microdroid_manager/src/main.rs
index 9c1792d..319ca2b 100644
--- a/microdroid_manager/src/main.rs
+++ b/microdroid_manager/src/main.rs
@@ -246,7 +246,8 @@
     info!("notifying payload started");
     service.notifyPayloadStarted(local_cid as i32)?;
 
-    if let Some(code) = child.wait()?.code() {
+    let exit_status = child.wait()?;
+    if let Some(code) = exit_status.code() {
         info!("notifying payload finished");
         service.notifyPayloadFinished(local_cid as i32, code)?;
 
@@ -256,7 +257,7 @@
             error!("task exited with exit code: {}", code);
         }
     } else {
-        error!("task terminated by signal");
+        error!("task terminated: {}", exit_status);
     }
     Ok(())
 }