restrict fbthrift python dependency to fix watchman-diag
restrict fbthrift python dependency to fix watchman-diag

Reviewed By: singhsrb

Differential Revision: D33982894

fbshipit-source-id: 5ec3f1555a551f3931983fde844346293704231c

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