Bug 3849: Duplicate certificate sent when using https_port

Bug 3849: Duplicate certificate sent when using https_port

The certificate file given with the "cert=" option it may contain a list of
certificates to be chained to the SSL client, for example intermediate
certificates.
The bug caused because in the certificates  chain we are storing also the
certificate of the port. This is works well for SSL-bump because squid
generates a certificate which uses the port certificate as CA certificate.
But in the case of https_port without bumping the port certificate is sent
twice, one as SSL server certificate and one as chained certificate.

This patch try to chain port certificate only when the sslbump is used.

This is a Measurement Factory project