MINOR: quic: Transport parameters encoding without version_information

MINOR: quic: Transport parameters encoding without version_information

Encode the version_information parameter only if the chosen version is provided
to quic_transport_params_encode() whose aim is to encode into a buffer all the
transport parameters passed as parameter (struct quic_params *p) in addition
to the version_information parameter.

This enables the support of transport parameters encoding without
the version_information transport parameter. This is useful for build against TLS stacks
as boringssl, aws-lc where a subset of the listener transport parameters
without version_information must be set as context string for acception
early data (see https://commondatastorage.googleapis.com/chromium-boringssl-docs/ssl.h.html#SSL_set_quic_early_data_context).

This patch is required to make haproxy builds against aws-lc TLS stack
(USE_OPENSSL_AWSLC) support 0-RTT. Does not impact the others builds.