cryptohome: Add RemoveEx method and remove unused Remove.

The Remove method from cryptohome is never used, and this adds a new
RemoveEx method, which will allow the AsyncRemove method to be deleted
eventually.

BUG=chromium:211405
TEST=test_that -b ${BOARD} login_Cryptohome

Change-Id: I46158a32ef65d18a00a15d50ad811f4a6465d39c
Reviewed-on: https://chromium-review.googlesource.com/1091177
Commit-Ready: Greg Kerr <kerrnel@chromium.org>
Tested-by: Greg Kerr <kerrnel@chromium.org>
Reviewed-by: Greg Kerr <kerrnel@chromium.org>
Reviewed-by: Andrey Pronin <apronin@chromium.org>
2 files changed