Disable Python linters on Azure pipelines.

This patch disables execution of Python lintes on Azure pipelines, as
they are now executed through Github Actions.

tests/azure/azure-pipelines.yml

@@ -18,27 +18,6 @@ pool:
   vmImage: 'ubuntu-18.04'
 
 stages:
-- stage: Linters
-  jobs:
-  - job: RunLinters
-    displayName: Run Linters
-    steps:
-    - task: UsePythonVersion@0
-      inputs:
-        versionSpec: '3.6'
-
-    - script: python -m pip install --upgrade pip setuptools wheel
-      displayName: Install tools
-
-    - script: pip install pydocstyle flake8
-      displayName: Install dependencies
-
-    - script: flake8 .
-      displayName: Run flake8 checks
-
-    - script: pydocstyle .
-      displayName: Verify docstings
-
 - stage: Centos7
   dependsOn: []
   jobs: