create_degenerate_pkcs7 returns certificates out of order

[sbansal3096]

CertificateSet used in create_degenerate_pkcs7 causes the certificates order to change.
Accoridng to RFC: https://tools.ietf.org/html/rfc8894#section-3.3.2.1:

The reply must contain the issued certificate. It may also contain additional certificates, but the issued certificate MUST be the leaf certificate.

This causes the request to fail at times.

[mosen]

Thanks @sbansal3096 i did not look at this project for a while but this is helpful.