Move to dictionary list of projects zuul._projects (take 2)

This re-implements I430277369f9ecb2ecc0a31f795c72bba83bcecff (that had
to be reverted with commit c8628dd8f8).

The original change had a small syntax error using
"zuul.projects.values()" instead of "zuul._projects.values()".  This
is corrected here.

It also had a problem with_items: zuul._projects.values() -- in
python3 this returns a view, which doesn't work with "with_items:"
... so you need to "| list".

Integration test results (for use-cached-repos at least) in
I7828f78efd1d20031cf1c34629200f265576e7a7.

Change-Id: I9d88f405f34d1c5f75ebf4f52cedfaaab20c3bda

playbooks/release/pre.yaml

@@ -5,7 +5,7 @@
       command: "git remote add origin https://{{ item.canonical_name }}"
       args:
         chdir: "{{ ansible_user_dir }}/src/{{ item.canonical_name }}"
-      with_items: "{{ zuul.projects }}"
+      with_items: "{{ zuul._projects.values() | list }}"
   roles:
     - role: configure-git
       git_config:

roles/use-cached-repos/tasks/main.yaml

@@ -1,7 +1,7 @@
 - name: Find locally cached git repos
   stat:
     path: "/opt/git/{{ item.name }}"
-  with_items: "{{ zuul.projects }}"
+  with_items: "{{ zuul._projects.values() | list }}"
   register: cached_repos
 
 - name: Clone cached repo to workspace
@@ -10,7 +10,7 @@
     creates: "{{ ansible_user_dir }}/{{ item.0.src_dir}}"
   when: item.1.stat.exists
   with_together:
-    - "{{ zuul.projects }}"
+    - "{{ zuul._projects.values() | list }}"
     - "{{ cached_repos.results }}"
 
 - name: Clone upstream repo to workspace
@@ -19,11 +19,11 @@
     creates: "{{ ansible_user_dir }}/{{ item.0.src_dir}}"
   when: not item.1.stat.exists
   with_together:
-    - "{{ zuul.projects }}"
+    - "{{ zuul._projects.values() | list }}"
     - "{{ cached_repos.results }}"
 
 - name: Remove origin from local git repos
   command: "git remote rm origin"
   args:
     chdir: "{{ ansible_user_dir }}/{{ item.src_dir}}"
-  with_items: "{{ zuul.projects }}"
+  with_items: "{{ zuul._projects.values() | list }}"