Fork from haproxy/haproxy to develop a solution for the TLS error case.
(haproxy#693)

Aim of this fork is to implement client certificate details into the haproxy source code.
This details should be then prepared and transferd to the underlaying haproxy log system.

Users should be able to use the outcome as a patch for their haproxy and get the ability to debug a tls connection which was interrupted by certificate reasons.

New features are:
Log: 
- Client certificate issuer name
- Client certificate subject name
- Client certificate fingerprint
- Client certificate serial

Activation of this verbose log:

This patch is intruducing a new keyword inside the configuration file. (verbose-tls-err-log)
The "verbose-tls-err-log" needs to be inserted into the "global" section.