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
diff --git a/ui/build/paths/config.go b/ui/build/paths/config.go
index 4275601..9d67a62 100644
--- a/ui/build/paths/config.go
+++ b/ui/build/paths/config.go
@@ -71,6 +71,7 @@
 	"dd":        Allowed,
 	"diff":      Allowed,
 	"dirname":   Allowed,
+	"du":        Allowed,
 	"echo":      Allowed,
 	"egrep":     Allowed,
 	"env":       Allowed,
@@ -97,6 +98,7 @@
 	"mktemp":    Allowed,
 	"mv":        Allowed,
 	"openssl":   Allowed,
+	"paste":     Allowed,
 	"patch":     Allowed,
 	"perl":      Allowed,
 	"pgrep":     Allowed,
@@ -135,6 +137,7 @@
 	"whoami":    Allowed,
 	"xargs":     Allowed,
 	"xmllint":   Allowed,
+	"xxd":       Allowed,
 	"xz":        Allowed,
 	"zip":       Allowed,
 	"zipinfo":   Allowed,