[watchman] log unexpected errors in watch_project
[watchman] log unexpected errors in watch_project

Summary: `watch_project` has a catch-all error handler. it assumes that if the request errored then the path doesn't exist, but that's not true; the request can error for other reasons, so let's see what they are by logging them.

Reviewed By: nmote

Differential Revision: D27710139

fbshipit-source-id: 02ba51319a38053fb4034a8568946d3d33a226c9

mroch/flow,facebook/flow,mroch/flow,mroch/flow,facebook/flow,facebook/flow,mroch/flow,facebook/flow,mroch/flow,facebook/flow,mroch/flow,facebook/flow,mroch/flow,facebook/flow