Move delete_files_relative
Move delete_files_relative

Summary: Make this usable from any pass.

Reviewed By: ssj933

Differential Revision: D32011528

fbshipit-source-id: 82478e7a6b649972e5c1a83ad9763a990a40e883

facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex