Move to dictionary list of projects zuul._projects

Zuul exports the projects list as a dictionary in _projects in the
depends-on.  The idea is that we switch these jobs to that, and do
some testing.  When ready, we switch "projects" to be the dictionary
view, and revert "_project" calls here to "project".

Change-Id: I430277369f9ecb2ecc0a31f795c72bba83bcecff

playbooks/release/pre.yaml

@@ -6,7 +6,7 @@
       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() }}"
 
   roles:
     - legacy-copy-project-config-scripts

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() }}"
   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() }}"
     - "{{ cached_repos.results }}"
 
 - name: Clone upstream repo to workspace
@@ -19,7 +19,7 @@
     creates: "{{ ansible_user_dir }}/{{ item.0.src_dir}}"
   when: not item.1.stat.exists
   with_together:
-    - "{{ zuul.projects }}"
+    - "{{ zuul.projects.values() }}"
     - "{{ cached_repos.results }}"
 
 - name: Remove origin from local git repos