Android: sdcardfs: Don't complain in fixup_lower_ownership

Not all filesystems support changing the owner of a file.
We shouldn't complain if it doesn't happen.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
Bug: 37488099
Change-Id: I403e44ab7230f176e6df82f6adb4e5c82ce57f33