In issue #940, it was reported that the crt-list does not work correctly
anymore. Indeed when inserting a crt-list line which use a certificate
previously seen in the crt-list, this one won't be inserted in the SNI
list and will be silently ignored.
This bug was introduced by commit 47da821 "MEDIUM: ssl: emulates the
multi-cert bundles in the crtlist".
This patch also includes a reg-test which tests this issue.
This bugfix must be backported in 2.3.
