disable prefetch when globbing from eden
disable prefetch when globbing from eden

Summary:
This is counterproductive for fresh instance results in large repos;
now that we can be lazy we can just turn it off.

Reviewed By: strager

Differential Revision: D8584082

fbshipit-source-id: 01f194e2e052f61917fa4fe7dafbcb604ba76842

wez/watchman,wez/watchman,facebook/watchman,facebook/watchman,nodakai/watchman,wez/watchman,nodakai/watchman,wez/watchman,wez/watchman,nodakai/watchman,facebook/watchman,wez/watchman,wez/watchman,facebook/watchman,facebook/watchman,nodakai/watchman,facebook/watchman,nodakai/watchman,nodakai/watchman,nodakai/watchman,facebook/watchman,wez/watchman,nodakai/watchman,facebook/watchman,facebook/watchman,nodakai/watchman,wez/watchman