manifest_version.py: add dashboard_url as constructor parameter
manifest_version.py: add dashboard_url as constructor parameter

This CL is a temporary fix to allow the commit queue to run.
dashboard_url is not used yet as of this CL.

BUG=None
TEST=None

Change-Id: I37a3a37eddef31cb0d1f6e5ba87c84e1c09a0b8b
Reviewed-on: https://chromium-review.googlesource.com/181668
Tested-by: Aviv Keshet <178e8ae417efbe404feca7ab4cb8f0ba8c109369@chromium.org>
Reviewed-by: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>
Commit-Queue: Aviv Keshet <178e8ae417efbe404feca7ab4cb8f0ba8c109369@chromium.org>

bpsinc-native/src_third_party_chromite,bpsinc-native/src_third_party_chromite,chadversary/chromiumos.chromite,bpsinc-native/src_third_party_chromite,chadversary/chromiumos.chromite