Output sphinx error message on report generation error

[ArturGajowy]

When there are syntax errors in .rst files, an attempt to generate the sphinx report ends with

[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 58.042 s
[INFO] Finished at: 2017-01-02T21:48:35+01:00
[INFO] Final Memory: 60M/597M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal io.airlift.maven.plugins:sphinx-maven-plugin:2.0:generate (default) on project presto-docs: Failed to run the report: Sphinx report generation failed -> [Help 1]
[ERROR] 

Running with -e does not improve on that.

The expected behaviour would be to output the sphinx error message unchanged.

Note: sphinx outputs errors using stderr, at least on my machine.

[electrum]

I replaced stderr in SphinxRunner with System.setErr() and it never prints anything to stderr, even with -v and -T.

[cryptoe]

@ArturGajowy
I used http://rst.ninjs.org/ to figure out rst issues and when it when the plugin was failing on consistency check, added the new file in the toctree.

[xkwangcn]

so, how to resolve this at last?