Do not erroneously reinit NSS in Dogtag interface
The Dogtag interface always attempts to (re)init NSS, which can fail
with SEC_ERROR_BUSY. Do not reinitialise NSS when it has already
been initialised with the given dbdir.
Part of: https://fedorahosted.org/freeipa/ticket/5459
Reviewed-By: Jan Cholasta <jcholast@redhat.com>