cherry-pick change to disable rate limiting in live-server live session

debian/changelog

@@ -1,7 +1,12 @@
 livecd-rootfs (2.525.6) UNRELEASED; urgency=medium
 
+  [ Steve Langasek ]
   * generate all tar files with --xattrs.  LP: #1302192.
 
+  [ Michael Hudson-Doyle ]
+  * Disable journald rate limiting in the live-server live session. 
+    (LP: #1776891) 
+
  -- Steve Langasek <steve.langasek@ubuntu.com>  Wed, 01 Aug 2018 20:57:14 -0700
 
 livecd-rootfs (2.525.5) bionic; urgency=medium

live-build/ubuntu-server/includes.binary/overlay/etc/systemd/journald.conf.d/no-rate-limit.conf

@@ -0,0 +1 @@
+RateLimitIntervalSec=0