The "abort ssl cert" command is buggy and removes the current ckch store, and instances, leading to SNI removal. It must only removes the new one. This patch also adds a check in set_ssl_cert.vtc and set_ssl_server_cert.vtc. Must be backported as far as 2.2.
File list: - common.pem: PEM file which may be used by most of the VTC files.