TF: add plantuml wrapper script

TF-A documentation build triggers the following python exception:

    Exception occurred:
      File "/usr/local/lib/python3.6/dist-packages/sphinxcontrib/plantuml.py", line 352, in _prepare_html_render
        self.builder.warn(str(err))
    AttributeError: 'StandaloneHTMLBuilder' object has no attribute 'warn'
    The full traceback has been saved in /tmp/sphinx-err-oyao8gvj.log, if you want to report the issue to the developers.
    Please also report this if it was a user error, so that a better error message can be provided next time.
    A bug report can be filed in the tracker at <https://github.com/sphinx-doc/sphinx/issues>. Thanks!
    Makefile:25: recipe for target 'html' failed
    make[2]: *** [html] Error 2
    Makefile:1295: recipe for target 'doc' failed
    make[1]: *** [doc] Error 2

It's caused by sphinx trying to run plantuml command which doesn't exist
since we install the jar manually. Add a wrapper shell script to fix the
issue.

Signed-off-by: Leonardo Sandoval <leonardo.sandoval@linaro.org>
Signed-off-by: Fathi Boudra <fathi.boudra@linaro.org>
Change-Id: Ie48273ee50581ca7c32f13629f6e95b18882b912
2 files changed