Migrate header variable into rest client

Author: Gonchik Tsymzhitov

atlassian/rest_client.py

@@ -18,6 +18,7 @@ class AtlassianRestAPI(object):
     form_token_headers = {'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8',
                           'X-Atlassian-Token': 'no-check'}
     no_check_headers = {'X-Atlassian-Token': 'no-check'}
+    experimental_headers_general = {'X-Atlassian-Token': 'no-check', 'X-ExperimentalApi': 'opt-in'}
     response = None
 
     def __init__(self, url, username=None, password=None, timeout=60, api_root='rest/api', api_version='latest',

atlassian/service_desk.py

@@ -432,10 +432,7 @@ def attach_temporary_file(self, service_desk_id, filename):
         url = 'rest/servicedeskapi/servicedesk/{}/attachTemporaryFile'.format(service_desk_id)
 
         with open(filename, 'rb') as file:
-            headers = {
-                        'X-Atlassian-Token': 'no-check',
-                        'X-ExperimentalApi': 'opt-in'}
-            result = self.post(path=url, headers=headers,
+            result = self.post(path=url, headers=self.experimental_headers_general,
                                files={'file': file}).get('temporaryAttachments')
             temp_attachment_id = result[0].get('temporaryAttachmentId')