Use ensure-twine role to ensure twine exists

Depends-On: Ic00e4f0c08fc42ce9d68f39be8522b6c2bba6396
Change-Id: Id1ce97fee85df24675b32af9d610a3323591a8d4

playbooks/publish/pypi.yaml

@@ -1,24 +1,5 @@
 - hosts: localhost
   roles:
+    - ensure-twine
     - role: upload-pypi
       pypi_path: "{{ zuul.executor.work_root }}/artifacts"
-
-  pre_tasks:
-    - name: Check for twine install
-      command: which twine
-      ignore_errors: yes
-      register: register_twine
-
-    - name: Set pypi_twine_executable
-      set_fact:
-        pypi_twine_executable: "{{ register_twine.stdout }}"
-      when: register_twine|succeeded
-
-    - name: Ensure twine is installed
-      command: pip install twine --user
-      when: pypi_twine_executable is not defined
-
-    - name: Set pypi twine executable
-      set_fact:
-        pypi_twine_executable: ~/.local/bin/twine
-      when: pypi_twine_executable is not defined