Add a bug reference and upload to Bionic.

debian/changelog

@@ -1,10 +1,10 @@
-lubuntu-default-settings (0.54.2) UNRELEASED; urgency=medium
+lubuntu-default-settings (0.54.2) bionic; urgency=medium
 
   * Remove /usr/share/xsessions/QLubuntu.desktop from
     lubuntu-default-settings.install so dh_missing does not make the build
-    FTBFS.
+    FTBFS (LP: #1786602).
 
- -- Simon Quigley <tsimonq2@ubuntu.com>  Sun, 30 Sep 2018 15:55:14 -0500
+ -- Simon Quigley <tsimonq2@ubuntu.com>  Sun, 03 Feb 2019 23:56:24 -0600
 
 lubuntu-default-settings (0.54.1) bionic; urgency=medium