OpenSSL: Add support for Brainpool Elliptic Curves
This allows the IKE groups 27-30 (RFC 6932) to be used with OpenSSL
1.0.2 and newer. For now, these get enabled for SAE as configurable
groups (sae_groups parameter), but the new groups are not enabled by
default.
Signed-off-by: Jouni Malinen <j@w1.fi>