Properly setup the chroot before using the network in buildd hook.

debian/changelog

@@ -1,3 +1,9 @@
+livecd-rootfs (2.634) UNRELEASED; urgency=medium
+
+  * Properly setup the chroot before using the network.
+
+ -- David Krauser <david.krauser@canonical.com>  Thu, 12 Dec 2019 13:50:58 -0400
+
 livecd-rootfs (2.633) focal; urgency=medium
 
   * Snapd for uc20 model assertions does not support global channel overrides.

live-build/buildd/hooks/48-policy-rc-d.binary

@@ -1,7 +1,18 @@
 #!/bin/sh
+
 set -e
 
 # This is run after 02-disk-image-uefi.binary because
 # we don't want policyrcd-script-zg2 installed in
 # bootable images.
+
+. config/functions
+
+cleanup() {
+    teardown_mountpoint chroot
+}
+trap cleanup EXIT
+
+setup_mountpoint chroot
+
 chroot chroot apt-get install -y policyrcd-script-zg2