@Override
    public CertificateStore get() { return instance; }
An certificate store provider which provides a factory which throws exception on
invocation - as no certificate store is currently provided by default.
The purpose of this is to provide a certificate store for injection in the case where
no certificate store component is provided.

@author bratseth
container-disc/src/main/java/com/yahoo/container/jdisc/CertificateStoreProvider.java