Fix nightly build log fetching

Bug: translateselectedtext:10
Change-Id: If018242ef541df5798f77d4e215427705d7270b0
diff --git a/playbooks/nightly-build/post.yaml b/playbooks/nightly-build/post.yaml
index 0c4ede9..ae09c36 100644
--- a/playbooks/nightly-build/post.yaml
+++ b/playbooks/nightly-build/post.yaml
@@ -2,3 +2,5 @@
   hosts: all
   roles:
     - fetch-cws-upload-log
+  vars:
+    workingDirectory: "{{ zuul.project.src_dir }}/out"