Change default journal mode to PERSIST.

         PERSIST may improve performance by reducing how often journal blocks are

         reallocated (compared to truncation) resulting in better data block locality

         and less churn of the storage media. -->

    <string name="db_default_journal_mode">TRUNCATE</string>

    <string name="db_default_journal_mode">PERSIST</string>

    <!-- Maximum size of the persistent journal file in bytes.

         If the journal file grows to be larger than this amount then SQLite will