Fix dev roller recipe to fetch the old tools/VERSION file

Change-Id: I1a6b9079f44dd2054cd7ac099fb7bd1c746d5ac7
Reviewed-on: https://dart-review.googlesource.com/c/recipes/+/163780
Reviewed-by: Alexander Thomas <athom@google.com>
Commit-Queue: Alexander Thomas <athom@google.com>
2 files changed