[PATCH] doc/conf.py: Remove _static from html_static_path

[David Bremner]

"W. Trevor King" <wking at tremily.us> writes:

> Avoid:
>
>   $ make HAVE_SPHINX=1 sphinx-html
>   python ./doc/mkdocdeps.py ./doc doc/_build doc/docdeps.mk
>   sphinx-build -b html -d doc/_build/doctrees -q ./doc doc/_build/html
>   Making output directory...
>   WARNING: html_static_path entry '/home/wking/src/notmuch/notmuch/doc/_static' does not exist

pushed to release and master

d