BUG/MEDIUM: ssl: free the ckch instance linked to a server

This patch unlinks and frees the ckch instance linked to a server during
the free of this server.

This could have locked certificates in a "Used" state when removing
servers dynamically from the CLI. And could provoke a segfault once we
try to dynamically update the certificate after that.

This must be backported as far as 2.4.
1 file changed