* pkcs11-register: Fixed detection of already registered OpenSC
Anny configuration of onepin-opensc-pkcs11.so and opensc-pkcs11.so
should be enough to skip registering the default module again.
* Use onepin module for generic NSS DB
fixes https://github.com/OpenSC/OpenSC/issues/1818
May have the disadvantage that some other programs that use NSS don't
see the signature keys. However, we currently only know for sure that
Chromium is using the generic NSS DB.