Fix CH test_store_pull_request

ERROR: test_store_pull_request (nxtools.hooks.tests.webhooks.github_handlers.test_pullrequest_store.GithubStorePullRequestHandlerTest)
Traceback (most recent call last):
  File "/opt/jenkins/workspace/tools-hooks-branches_master-I42XCCHS43V7F5ET543GIXXZIRQA5ROGL635RNILTDS6DOYTANKA/nuxeo-tools-hooks/nxtools/hooks/tests/webhooks/github_handlers/test_pullrequest_store.py", line 59, in test_store_pull_request
    self.handler._do_handle(body)
  File "/opt/jenkins/workspace/tools-hooks-branches_master-I42XCCHS43V7F5ET543GIXXZIRQA5ROGL635RNILTDS6DOYTANKA/nuxeo-tools-hooks/nxtools/hooks/endpoints/webhook/github_handlers/pull_request.py", line 44, in _do_handle
    stored_pull_request = self.store_pull_request(event)
  File "/opt/jenkins/workspace/tools-hooks-branches_master-I42XCCHS43V7F5ET543GIXXZIRQA5ROGL635RNILTDS6DOYTANKA/nuxeo-tools-hooks/nxtools/hooks/endpoints/webhook/github_handlers/pull_request.py", line 96, in store_pull_request
    return services.get(GithubService).create_pullrequest(event.organization, event.repository, event.pull_request)
  File "/opt/jenkins/workspace/tools-hooks-branches_master-I42XCCHS43V7F5ET543GIXXZIRQA5ROGL635RNILTDS6DOYTANKA/nuxeo-tools-hooks/nxtools/hooks/services/github_service.py", line 113, in create_pullrequest
    self.update_pullrequest_with_jira(stored_pr)
  File "/opt/jenkins/workspace/tools-hooks-branches_master-I42XCCHS43V7F5ET543GIXXZIRQA5ROGL635RNILTDS6DOYTANKA/nuxeo-tools-hooks/nxtools/hooks/services/github_service.py", line 123, in update_pullrequest_with_jira
    if jira_key is not None else None
  File "/opt/jenkins/workspace/tools-hooks-branches_master-I42XCCHS43V7F5ET543GIXXZIRQA5ROGL635RNILTDS6DOYTANKA/nuxeo-tools-hooks/nxtools/hooks/services/jira_service.py", line 73, in get_issue
    return self.__jira_client.issue(id, fields)
AttributeError: 'JiraService' object has no attribute '_JiraService__jira_client'
-------------------- >> begin captured logging << --------------------
nxtools.hooks.services.config: DEBUG: Get [general] CONF, default=/opt/jenkins/workspace/tools-hooks-branches_master-I42XCCHS43V7F5ET543GIXXZIRQA5ROGL635RNILTDS6DOYTANKA/nuxeo-tools-hooks/conf/nuxeo-tools-hooks.ini, env_key=NXTOOLS_HOOKS_CONF, request_value=None, os_value=nxtools/hooks/tests/resources/config.ini, config_value=/opt/jenkins/workspace/tools-hooks-branches_master-I42XCCHS43V7F5ET543GIXXZIRQA5ROGL635RNILTDS6DOYTANKA/nuxeo-tools-hooks/conf/nuxeo-tools-hooks.ini, value=nxtools/hooks/tests/resources/config.ini
nxtools.hooks.services.config: INFO: Loading config file: nxtools/hooks/tests/resources/config.ini
nxtools.hooks.services.config: DEBUG: Get [general] CONF, default=/opt/jenkins/workspace/tools-hooks-branches_master-I42XCCHS43V7F5ET543GIXXZIRQA5ROGL635RNILTDS6DOYTANKA/nuxeo-tools-hooks/conf/nuxeo-tools-hooks.ini, env_key=NXTOOLS_HOOKS_CONF, request_value=None, os_value=nxtools/hooks/tests/resources/config.ini, config_value=/opt/jenkins/workspace/tools-hooks-branches_master-I42XCCHS43V7F5ET543GIXXZIRQA5ROGL635RNILTDS6DOYTANKA/nuxeo-tools-hooks/conf/nuxeo-tools-hooks.ini, value=nxtools/hooks/tests/resources/config.ini
nxtools.hooks.services.config: INFO: Loading config file: nxtools/hooks/tests/resources/config.ini
nxtools.hooks.services.config: DEBUG: Get [general] CONF, default=/opt/jenkins/workspace/tools-hooks-branches_master-I42XCCHS43V7F5ET543GIXXZIRQA5ROGL635RNILTDS6DOYTANKA/nuxeo-tools-hooks/conf/nuxeo-tools-hooks.ini, env_key=NXTOOLS_HOOKS_CONF, request_value=None, os_value=nxtools/hooks/tests/resources/github_handlers/config.ini, config_value=/opt/jenkins/workspace/tools-hooks-branches_master-I42XCCHS43V7F5ET543GIXXZIRQA5ROGL635RNILTDS6DOYTANKA/nuxeo-tools-hooks/conf/nuxeo-tools-hooks.ini, value=nxtools/hooks/tests/resources/github_handlers/config.ini
nxtools.hooks.services.config: INFO: Loading config file: nxtools/hooks/tests/resources/github_handlers/config.ini
nxtools.hooks.services.config: DEBUG: Get [DatabaseService] connection_url, default=None, env_key=NXTOOLS_HOOKS_DATABASE_CONNECTION_URL, request_value=None, os_value=None, config_value=mongomock://localhost, value=mongomock://localhost
nxtools.hooks.endpoints.webhook.github_handlers.pull_request: INFO: GithubStorePullRequestHandler.handle
nxtools.hooks.entities.db_entities: INFO: Pull request nuxeo/nuxeo/pull/210 saved
nxtools.hooks.services.config: DEBUG: Get [JiraService] auth_type, default=None, env_key=NXTOOLS_HOOKS_JIRA_AUTH_TYPE, request_value=None, os_value=None, config_value=None, value=None
--------------------- >> end captured logging << ---------------------