Add debug logs to understand update start delay

Test: th
Bug: 352332753
Change-Id: I7c8f11409dc2a1312813b29a4c523b3fe17833c4
diff --git a/fs_mgr/libsnapshot/snapshot.cpp b/fs_mgr/libsnapshot/snapshot.cpp
index 3a474d7..4d55315 100644
--- a/fs_mgr/libsnapshot/snapshot.cpp
+++ b/fs_mgr/libsnapshot/snapshot.cpp
@@ -2876,6 +2876,7 @@
             return false;
         }
     }
+    LOG(INFO) << "Unmapped " << snapshots.size() << " partitions with snapshots";
 
     // Terminate the daemon and release the snapuserd_client_ object.
     // If we need to re-connect with the daemon, EnsureSnapuserdConnected()