Allows getting rid of the xsec_mscrypt / xsec_nss factory constructs.

Change-Id: Idcc3351f7cc3b37a65e6f78018f062439e48bc3d
Reviewed-on: https://gerrit.libreoffice.org/53463Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>