void migrationComplete() {
        this.initialValue = getValue();
    }
Resets the initial value of the property (used to detect if a restart is required). It should
be safe to assume that if a property has been migrated from XML to the database, no restart is
required so this is called post-migration.

For internal use only.
xmppserver/src/main/java/org/jivesoftware/util/SystemProperty.java