Add du, paste, xxd to allowed PATH tools

du is used by build/make/tools/releasetools/build_image.py
paste is used by system/core/rootdir/update_and_install_ld_config.mk
xxd is used by device/generic/goldfish/tools/mk_qemu_image.sh

Test: none
Change-Id: I707668578d1babe1b149c2c3f989e5f8be37d897