Add @manual annotation to bsd header
Add @manual annotation to bsd header

Summary: Mark the header as it is not a header provided by folly

Reviewed By: yfeldblum

Differential Revision: D18800770

fbshipit-source-id: 95c9dcdeb6f4b745f0bce859e4d9669c009c353a

facebook/folly,facebook/folly,facebook/folly,facebook/folly,facebook/folly