* cipher/ecc-curves.c (mpi_ec_get_elliptic_curve)
(mpi_ec_setup_elliptic_curve): Factor out from _gcry_mpi_ec_new.
(_gcry_mpi_ec_internal_new): New.
(_gcry_mpi_ec_new): Rewrite using mpi_ec_get_elliptic_curve and
mpi_ec_setup_elliptic_curve.