Merge "Drop unused PerBootDbKeepAlive type" into main am: 98e175b6f8 am: a5ee446635

Original change: https://android-review.googlesource.com/c/platform/system/security/+/3037727

Change-Id: Ic59d4aa63366033c2b7eaf21e58edf561ba1f438
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
diff --git a/keystore2/src/database.rs b/keystore2/src/database.rs
index dd64764..0cc982a 100644
--- a/keystore2/src/database.rs
+++ b/keystore2/src/database.rs
@@ -842,12 +842,6 @@
     }
 }
 
-/// Shared in-memory databases get destroyed as soon as the last connection to them gets closed.
-/// This object does not allow access to the database connection. But it keeps a database
-/// connection alive in order to keep the in memory per boot database alive.
-#[allow(dead_code)]
-pub struct PerBootDbKeepAlive(Connection);
-
 impl KeystoreDB {
     const UNASSIGNED_KEY_ID: i64 = -1i64;
     const CURRENT_DB_VERSION: u32 = 1;