Alwats returns a constant sub index for any hashing.
If using configuration, expects subIndex as the setting name,
and the sub index value as the setting value.
author: kimchy
configure(CompassSettings settings) Configures the constant sub index hash, expects subIndex as
the setting name, and the sub index value as the setting value.
Configures the constant sub index hash, expects subIndex as
the setting name, and the sub index value as the setting value.
Parameters: settings - The settings to configure by throws: CompassException -