Add ensure-output-dirs to base jobs

In support of the base job log/artifact/docs fetching rework, add
ensure-output-dirs to the sample base jobs as well.

Change-Id: I65241452e93cf7a8c85ea30035f806da78240050

playbooks/base-test/pre.yaml

@@ -5,6 +5,9 @@
     # This role ensures basic connectivity and produces some
     # helpful information in zuul-info/
     - validate-host
+    # This role ensures standard output directories are created
+    # on each remote node
+    - ensure-output-dirs
     # This roles copies the ansible inventory to zuul-info/
     # for debugging purposes
     - log-inventory

playbooks/base/pre.yaml

@@ -5,6 +5,9 @@
     # This role ensures basic connectivity and produces some
     # helpful information in zuul-info/
     - validate-host
+    # This role ensures standard output directories are created
+    # on each remote node
+    - ensure-output-dirs
     # This roles copies the ansible inventory to zuul-info/
     # for debugging purposes
     - log-inventory