Set RSA_FLAG_EXT_PKEY flag
Set RSA_FLAG_EXT_PKEY flag

From docs:
"""
This flag means the private key operations will be handled by
rsa_mod_exp and that they do not depend on the private key
components being present:
for example a key stored in external hardware. Without this flag
bn_mod_exp gets called when private key components are absent.
"""

Setting this flag allows BIND to identify RSA key (stored on a HSM)
as a private key. Otherwise, BIND fails to sign and to verify signs.

Fixes: https://github.com/OpenSC/libp11/issues/304
Signed-off-by: Stanislav Levin <d8f28bdabcfedd2870feddb04c5f1bca6a417bec@altlinux.org>

mouse07410/libp11,mtrojnar/libp11,OpenSC/libp11,dengert/libp11,mtrojnar/libp11,dengert/libp11,mouse07410/libp11,OpenSC/libp11