Omit version for v1 certificates.

When calling X509_set_version to set v1 certificate, that should mean
that the version number field is omitted.

(Imported from upstream's 8c0d19d8577c9a96b65622bfa92d0affd6bbb4ac)

Change-Id: If433fda7b6ccbd899f3379a38581c351cf4a82da