Add support for Accept-Language in HTTP test class

"Accept-Language" is used to test translations.

Fixes: https://pagure.io/freeipa/issue/7559
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Petr Vobornik <pvoborni@redhat.com>

ipatests/test_ipaserver/httptest.py

@@ -33,6 +33,7 @@ class Unauthorized_HTTP_test(object):
     host = api.env.host
     cacert = api.env.tls_ca_cert
     content_type = 'application/x-www-form-urlencoded'
+    accept_language = 'en-us'
 
     def send_request(self, method='POST', params=None):
         """
@@ -47,8 +48,9 @@ class Unauthorized_HTTP_test(object):
                 params = urllib.parse.urlencode(params, True)
         url = 'https://' + self.host + self.app_uri
 
-        headers = {'Content-Type' : self.content_type,
-                   'Referer' : url}
+        headers = {'Content-Type': self.content_type,
+                   'Accept-Language': self.accept_language,
+                   'Referer': url}
 
         conn = util.create_https_connection(
                 self.host, cafile=self.cacert)