* lisp/vc/vc.el (vc-delete-file): New NOCONFIRM parameter.
(vc-rename-file): New OK-IF-ALREADY-EXISTS parameter.
* lisp/dired-aux.el (dired-rename-file): Pass it.
* test/lisp/vc/vc-tests/vc-tests.el (vc-test--rename-file): Test
it. Also test moving files into an existing directory.