Without this, we check the wrong cert when SNI is used:
./check_tcp -H git.netsandbox.de -p 443 -D 30,10
OK - Certificate 'netsandbox.de' will expire on 2017-04-19 12:01
+0200/CEST.
./check_tcp -H git.netsandbox.de -p 443 -D 30,10 -N git.netsandbox.de
OK - Certificate 'git.netsandbox.de' will expire on 2017-04-15 14:06
+0200/CEST.
fixes#4936
Signed-off-by: Gunnar Beutner <gunnar.beutner@icinga.com>