Fix jstesnode software release test random failure

Fix this random failure we sometimes have, like [here](https://nexedijs.erp5.net/#/test_result_module/20200414-44DF7D23/11) by adding a promise so that test does not try to connect to a nginx that's not started yet

```
======================================================================
ERROR: test (test.TestJSTestNode)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "parts/slapos-repository/software/jstestnode/test/test.py", line 60, in test
    '%sjio/test/tests.html' % (connection_dict['nginx'], ), allow_redirects=False)
  File "eggs/requests-2.20.0-py2.7.egg/requests/api.py", line 75, in get
    return request('get', url, params=params, **kwargs)
  File "eggs/requests-2.20.0-py2.7.egg/requests/api.py", line 60, in request
    return session.request(method=method, url=url, **kwargs)
  File "eggs/requests-2.20.0-py2.7.egg/requests/sessions.py", line 524, in request
    resp = self.send(prep, **send_kwargs)
  File "eggs/requests-2.20.0-py2.7.egg/requests/sessions.py", line 637, in send
    r = adapter.send(request, **kwargs)
  File "eggs/requests-2.20.0-py2.7.egg/requests/adapters.py", line 516, in send
    raise ConnectionError(e, request=request)
ConnectionError: HTTPConnectionPool(host='::1', port=9443): Max retries exceeded with url: /jio/test/tests.html (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x7f9b01f4b310>: Failed to establish a new connection: [Errno 111] Connection refused',))

```

See merge request !733

software/jstestnode/buildout.hash.cfg

@@ -15,7 +15,7 @@
 
 [instance]
 filename = instance.cfg.in
-md5sum = e6203cba0084289edec2176b185d3427
+md5sum = 42e7d1825f5582fbe2c55977e5abc574
 
 [template-nginx-service]
 filename = template-nginx-service.sh.in

software/jstestnode/instance.cfg.in

@@ -2,6 +2,7 @@
 parts =
   nginx-service
   runTestSuite-instance
+  promises
   publish
 eggs-directory = ${buildout:eggs-directory}
 develop-eggs-directory = ${buildout:develop-eggs-directory}
@@ -22,6 +23,7 @@ log = $${:var}/log
 varnginx = $${:var}/nginx
 scripts = $${:etc}/run
 services = $${:etc}/service
+promise = $${:etc}/promise
 www = $${:srv}/www
 home = $${:etc}/home
 ssl = $${:etc}/ssl
@@ -51,15 +53,20 @@ recipe = slapos.cookbook:wrapper
 wrapper-path = $${directory:services}/$${:_buildout_section_name_}
 command-line =
   ${xserver:location}/bin/Xvfb
-    $${:display}
+    :$${:display}
     -screen 0 1024x768x24
     -fbdir $${directory:framebuffer}
 environment =
   XORG_LOCK_DIR=$${:lock-dir}
 
-display = :0
+display = 0
 lock-dir = $${directory:run}
 
+[xvfb-promise]
+recipe = slapos.cookbook:wrapper
+wrapper-path = $${directory:promise}/$${:_buildout_section_name_}
+command-line = bash -c "[ -S $${xvfb-instance:lock-dir}/.X11-unix/X$${xvfb-instance:display} ]"
+
 
 #################################
 # Nginx service
@@ -85,14 +92,27 @@ ssl_key = $${directory:ssl}/nginx.key
 ssl_csr = $${directory:ssl}/nginx.csr
 ssl_crt = $${directory:ssl}/nginx.crt
 
+[nginx-listen-promise]
+recipe = slapos.cookbook:check_port_listening
+path = $${directory:promise}/$${:_buildout_section_name_}
+hostname = $${nginx-configuration:ip}
+port = $${nginx-configuration:port}
+
+
 #################################
 # SlapOS service
 #################################
 [instance-parameter]
 recipe = slapos.cookbook:slapconfiguration
-computer = $${slap_connection:computer_id}
-partition = $${slap_connection:partition_id}
-url = $${slap_connection:server_url}
-key = $${slap_connection:key_file}
-cert = $${slap_connection:cert_file}
-configuration._ = {}
\ No newline at end of file
+computer = $${slap-connection:computer-id}
+partition = $${slap-connection:partition-id}
+url = $${slap-connection:server-url}
+key = $${slap-connection:key-file}
+cert = $${slap-connection:cert-file}
+configuration._ = {}
+
+[promises]
+recipe =
+depends =
+  $${nginx-listen-promise:recipe}
+  $${xvfb-promise:recipe}
\ No newline at end of file