CryptoManager: correct documentation
CryptoManager: correct documentation

The implementation of encryptionKeyInUse() contradicts the previous
documentation. Updating.

maemo-foss/accounts-sso-signon,plotters/accounts-sso.signond,maemo-foss/accounts-sso-signon,plotters/accounts-sso.signond,maemo-foss/accounts-sso-signon,plotters/accounts-sso.signond