REGTESTS: ssl: add the same cert for client/server

Add the same certificate in server and bind line so we can try to catch
problems like in issue #1748 when updating over the CLI.
diff --git a/reg-tests/ssl/set_ssl_cert.vtc b/reg-tests/ssl/set_ssl_cert.vtc
index 100d343..a0fe5e7 100644
--- a/reg-tests/ssl/set_ssl_cert.vtc
+++ b/reg-tests/ssl/set_ssl_cert.vtc
@@ -69,6 +69,8 @@
     listen ssl-lst
         bind "${tmpdir}/ssl.sock" ssl crt ${testdir}/common.pem strict-sni
         server s1 ${s1_addr}:${s1_port}
+	# dummy server used to test a change when the same crt is used as server and bind
+        server s2 ${s1_addr}:${s1_port} ssl crt ${testdir}/common.pem verify none weight 0
 
     listen other-ssl-lst
         bind "${tmpdir}/other-ssl.sock" ssl crt-list ${testdir}/set_default_cert.crt-list