Canary build: save CWS upload/publish log

Also, fix a bug in the upload/publish command and fail when it exits
with a non-zero return code and doesn't fail with a ITEM_NOT_UPDATABLE
error.

Bug: twpowertools:20
Change-Id: I309e72b4a938be55782d0a7a18c1905ceb6cf304
diff --git a/roles/fetch-cws-log/tasks/main.yaml b/roles/fetch-cws-log/tasks/main.yaml
new file mode 100644
index 0000000..faeb65b
--- /dev/null
+++ b/roles/fetch-cws-log/tasks/main.yaml
@@ -0,0 +1,14 @@
+- name: Is there a cws-log.txt
+  register: stat_log
+  stat:
+    path: "{{ zuul.project.src_dir }}/cws-log.txt"
+
+- name: Store on executor
+  when: stat_log.stat.exists
+  synchronize:
+    mode: pull
+    src: "{{ zuul.project.src_dir }}/cws-log.txt"
+    dest: "{{ zuul.executor.log_root }}/cws-log.txt"
+    verify_host: true
+    owner: no
+    group: no