Fix os.Rename cross-device issue

Copy first and then delete the stage file instead of os.Rename.

change references from kelseyhightower to glerchundi so that its possible to test if this works.

Revert "change references from kelseyhightower to glerchundi so that its possible to test if this works."

This reverts commit e8b426c03508ece49897604c01ba0d9c58b8e9c8.