When the client or server uses a specific protocol version, automatically
require that version to be enabled at compile time.
An explicit call is still needed in test cases that require a specific
protocol version (due to analyzing version-specific behavior, or checking
the version in logs), but do not force that specific protocol version, or that
force a specific version only on the openssl/gnutls side.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>