Disable the snapd.refresh.timer in the live server session.

debian/changelog

@@ -1,3 +1,9 @@
+livecd-rootfs (2.500) UNRELEASED; urgency=medium
+
+  * Disable the snapd.refresh.timer in the live server session.
+
+ -- Michael Hudson-Doyle <michael.hudson@ubuntu.com>  Thu, 08 Feb 2018 13:43:12 +1300
+
 livecd-rootfs (2.499) bionic; urgency=medium
 
   * live-build/auto/config: Take into account SUBPROJECT when setting seeded

live-build/ubuntu-server/includes.binary/overlay/etc/systemd/system/snapd.refresh.timer

@@ -0,0 +1 @@
+/dev/null