apt: Move sources into sources.list to make other packages happy
This resolves (partly) an issue with python-apt where it's complaining about a
missing /etc/apt/sources.list file.
Change-Id: Iecb8bd318e10551490369855acc89c4530ef4f08
(cherry picked from commit df3e541400f3bd1340403631e68d44f8e41478ba)
diff --git a/etc/runonce.d/99-cleanup-sources b/etc/runonce.d/99-cleanup-sources
new file mode 100755
index 0000000..27c7ca9
--- /dev/null
+++ b/etc/runonce.d/99-cleanup-sources
@@ -0,0 +1,5 @@
+#!/bin/bash
+
+cat /etc/apt/sources.list.d/multistrap-*.list >>/etc/apt/sources.list
+rm -f /etc/apt/sources.list.d/multistrap-*.list
+