The purpose of the tool is to generate a report, and one might want to redirect that into a file with ">report.log" or "| tee report.log". That currently doesn't work because the normal output goes to stderr, which is unexpected. There is also the automatically generated log file, but that doesn't mean that using stderr is okay.
Review at, http://lists.openembedded.org/pipermail/openembedded-core/2017-March/134378.html
Merge at, http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=1e3ef54408da5625e3558602cae409663e03c8f7
verified in commit 3e655f9c7f0f4f778dc9eedd9f7405fc84b4c9ad