user/key: create new keys file on same fs as destination
user/key: create new keys file on same fs as destination

Depending on the operating system Gandalf runs on, `os.Rename()` may
fail to move this file in case its new destination lies on a different
filesystem.

flaviamissi/gandalf,scorphus/gandalf,scorphus/gandalf,flaviamissi/gandalf,tsuru/gandalf,tsuru/gandalf