[Perf] Change log URL addition for HistogramSet (OBBS)

This is the One-BuildBot-Step version of this change:
https://chromium-review.googlesource.com/c/chromium/tools/build/+/1038751

It will be safe to land once
https://chromium-review.googlesource.com/c/catapult/+/1029170 rolls into
Chromium.

Bug: catapult:#4397
Change-Id: I2358970703782a2d09940e580d7e8b06ea910726
Reviewed-on: https://chromium-review.googlesource.com/1038783
Reviewed-by: Simon Hatch <simonhatch@chromium.org>
Reviewed-by: Emily Hanley <eyaich@chromium.org>
Commit-Queue: Ethan Kuefner <eakuefner@chromium.org>
Cr-Commit-Position: refs/heads/master@{#556107}

tools/perf/core/results_dashboard.py

@@ -203,7 +203,8 @@ def MakeHistogramSetWithDiagnostics(histograms_file,
 
   url = _MakeStdioUrl(test_name, buildername, buildnumber)
   if url:
-    add_diagnostics_args.extend(['--log_urls', url])
+    add_diagnostics_args.extend(['--log_urls_k', 'Buildbot stdio'])
+    add_diagnostics_args.extend(['--log_urls_v', url])
 
   for k, v in revisions_dict.iteritems():
     add_diagnostics_args.extend((k, v))