cryptohome: Test for symlinks before copying attestation file.

BUG=chromium:649039
TEST=Rebooted device with normal file vs. symlink.

Change-Id: I3a86d5bec4495f8a0dd9e038ab3278bd394517d8
Reviewed-on: https://chromium-review.googlesource.com/388186
Commit-Ready: Ricky Zhou <rickyz@chromium.org>
Tested-by: Ricky Zhou <rickyz@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
1 file changed