Replace a cp with a user_cp.

Slightly cleaner, and should be equivalent.
We are, after all, creating file in the users dir here.

BUG=None
TEST=None

Change-Id: I2c5ce319878dbe496fc652a521b5b495d897398f
Reviewed-on: https://gerrit.chromium.org/gerrit/57825
Reviewed-by: David James <davidjames@chromium.org>
Commit-Queue: Peter Mayo <petermayo@chromium.org>
Tested-by: Peter Mayo <petermayo@chromium.org>
diff --git a/sdk_lib/make_chroot.sh b/sdk_lib/make_chroot.sh
index f9fb77a..9f1ac23 100755
--- a/sdk_lib/make_chroot.sh
+++ b/sdk_lib/make_chroot.sh
@@ -295,7 +295,7 @@
 
    if [[ "${SUDO_USER}" = "chrome-bot" && -d "${SUDO_HOME}/.ssh" ]]; then
      # Copy ssh keys, so chroot'd chrome-bot can scp files from chrome-web.
-     cp -rp "${SUDO_HOME}/.ssh" "$FLAGS_chroot/home/${SUDO_USER}/"
+     user_cp -rp "${SUDO_HOME}/.ssh" "$FLAGS_chroot/home/${SUDO_USER}/"
    fi
 
    if [[ -f ${SUDO_HOME}/.gitconfig ]]; then