Revert "Enable write-ahead logging for keystore db."

This reverts commit 6a50983169bc64f50b3747f6079df7a0a35c86b6.

Reason for revert: Bug 187889158. We forgot to account for database locks in the WAL mode set, and apparently some devices are running into locked dbs.

Change-Id: I43f8cb231397adc69ac6286b64a943cff55629c1
diff --git a/keystore2/src/database.rs b/keystore2/src/database.rs
index b6c459a..4ab4258 100644
--- a/keystore2/src/database.rs
+++ b/keystore2/src/database.rs
@@ -987,12 +987,6 @@
                     return Err(e);
                 }
             }
-            let result: String = conn
-                .pragma_update_and_check(None, "journal_mode", &"WAL", |row| row.get(0))
-                .expect("Attempting to set journal mode failed.");
-            if result != "wal" {
-                error!("Failed to put DB in WAL mode.  This will make keystore slow.");
-            }
             break;
         }
 
diff --git a/keystore2/vpnprofilestore/lib.rs b/keystore2/vpnprofilestore/lib.rs
index 5883ee1..8b3bc2b 100644
--- a/keystore2/vpnprofilestore/lib.rs
+++ b/keystore2/vpnprofilestore/lib.rs
@@ -24,7 +24,6 @@
 };
 use anyhow::{Context, Result};
 use keystore2::{async_task::AsyncTask, legacy_blob::LegacyBlobLoader, utils::watchdog as wd};
-use log::error;
 use rusqlite::{
     params, Connection, OptionalExtension, Transaction, TransactionBehavior, NO_PARAMS,
 };
@@ -47,15 +46,6 @@
         db.conn.busy_handler(None).context("Failed to set busy handler.")?;
 
         db.init_tables().context("Trying to initialize vpnstore db.")?;
-
-        let result: String = db
-            .conn
-            .pragma_update_and_check(None, "journal_mode", &"WAL", |row| row.get(0))
-            .expect("Attempting to set journal mode failed.");
-        if result != "wal" {
-            error!("Failed to put DB in WAL mode.  This will make keystore slow.");
-        }
-
         Ok(db)
     }