init: clean up exec command

Add wait time log for exec service execution time
Fix memory leak when exec service failed to start

Test: on marlin
Bug: 34518530
Change-Id: I01736bd9b1429414f3dc91dd5d02d88a681f0985
diff --git a/init/service.cpp b/init/service.cpp
index 0f7f62f..e186f27 100644
--- a/init/service.cpp
+++ b/init/service.cpp
@@ -997,7 +997,7 @@
     }
 
     if (svc->Reap()) {
-        waiting_for_exec = false;
+        stop_waiting_for_exec();
         RemoveService(*svc);
     }