Fix a comment
Fix a comment

Reviewed By: yfeldblum

Differential Revision: D4965608

fbshipit-source-id: db8d67ca7174e0296fbd8da2e1fe90cbbcef9496

Orvid/folly,facebook/folly,Orvid/folly,Orvid/folly,rklabs/folly,rklabs/folly,facebook/folly,rklabs/folly,facebook/folly,Orvid/folly,facebook/folly,rklabs/folly,Orvid/folly,facebook/folly,rklabs/folly