Fix sphinx publishing

Since change I9ed0b02d6ca20a6b679507c4d988531abc55b09d merged, we were
publishing to docs.o.o/$project/latest/html instead of
docs.o.o/$project/latest . We need to remove the final html part when
using rsync. Add an option to allow appending "/" to sphinx_output_src
so that rsync copies the content without the final html.

Change-Id: I0eed5ebf5af8d43f6a105a1fc0dcf1b0a9813dbd

roles/fetch-sphinx-output/README.rst

@@ -16,8 +16,15 @@ to the log root of the executor.
 
    Directory relative to zuul_work_dir where build output will be put.
 
+.. zuul:rolevar:: sphinx_output_suffix
+   :default: ''
+
+   Suffix to use for constructing the path. This is normally an
+   empty string. If set to '/' then, rsync will remove the last part
+   from the original path.
+
 .. zuul:rolevar:: sphinx_output_src
-   :default: {{ zuul_work_dir }}/{{ sphinx_build_dir }}/html
+   :default: {{ zuul_work_dir }}/{{ sphinx_build_dir }}/html{{ sphinx_output_suffix }}
 
    The location on the worker from which to fetch the generated sphinx
    content.  By default, the HTML doc build dir of the current

roles/fetch-sphinx-output/defaults/main.yaml

@@ -2,4 +2,5 @@
 zuul_executor_dest: "{{ zuul.executor.log_root }}"
 zuul_work_dir: "{{ zuul.project.src_dir }}"
 sphinx_build_dir: doc/build
-sphinx_output_src: "{{ zuul_work_dir }}/{{ sphinx_build_dir }}/html"
+sphinx_output_suffix: ""
+sphinx_output_src: "{{ zuul_work_dir }}/{{ sphinx_build_dir }}/html{{ sphinx_output_suffix }}"