live-build/ubuntu-cpc/functions: call apt-get update in the chroot

after mounting a blank /var/lib/apt, so that further operations work
as expected.

debian/changelog

@@ -1,3 +1,11 @@
+livecd-rootfs (2.408.16) UNRELEASED; urgency=medium
+
+  * live-build/ubuntu-cpc/functions: call apt-get update in the chroot
+    after mounting a blank /var/lib/apt, so that further operations work
+    as expected.
+
+ -- Steve Langasek <steve.langasek@ubuntu.com>  Tue, 12 Sep 2017 13:24:27 -0700
+
 livecd-rootfs (2.408.15) xenial; urgency=medium
 
   [ Mathieu Trudel-Lapierre ]

live-build/ubuntu-cpc/functions

@@ -90,6 +90,7 @@ setup_mountpoint() {
     mount -t tmpfs none "$mountpoint/var/cache/apt"
     mv "$mountpoint/etc/resolv.conf" resolv.conf.tmp
     cp /etc/resolv.conf "$mountpoint/etc/resolv.conf"
+    chroot "$mountpoint" apt-get update
 
 }