debootstrap: fix host-user-contaminated

Fix QA warning:
WARNING: QA Issue: debootstrap: /debootstrap/usr/share/debootstrap/scripts/gutsy is owned by uid 1000,
which is the same as the user running bitbake. This may be due to host contamination [host-user-contaminated]

Signed-off-by: Yi Zhao <yi.zhao@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>