Finalise changelog

debian/changelog

@@ -1,4 +1,4 @@
-livecd-rootfs (2.578.6) UNRELEASED; urgency=medium
+livecd-rootfs (2.578.6) disco; urgency=medium
 
   [ Tobias Koch ]
   * Do proper error checking when calling snap-tool info to determine
@@ -11,7 +11,7 @@ livecd-rootfs (2.578.6) UNRELEASED; urgency=medium
   * Seed core for non minimized builds, as it is still required (LP:
     #1836594).
 
- -- Tobias Koch <tobias.koch@canonical.com>  Tue, 16 Jul 2019 11:27:10 +0200
+ -- Iain Lane <iain.lane@canonical.com>  Tue, 16 Jul 2019 13:20:52 +0100
 
 livecd-rootfs (2.578.5) disco; urgency=medium