Transfer ownership of UMA.CleanExitBeaconConsistency.

R=asvitkine@chromium.org, chromium-metrics-reviews@google.com

Bug: 1089602
Change-Id: I76015e47077e8ee14fdd8a915009cf21c10d08b9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2485294
Commit-Queue: Sigurður Ásgeirsson <siggi@chromium.org>
Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#818535}

tools/metrics/histograms/histograms_xml/uma/histograms.xml

@@ -44,7 +44,7 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 
 <histogram name="UMA.CleanExitBeaconConsistency" enum="UmaCleanExitConsistency"
     expires_after="M85">
-  <owner>siggi@chromium.org</owner>
+  <owner>asvitkine@chromium.org</owner>
   <owner>src/base/metrics/OWNERS</owner>
   <summary>
     Reports the combined state of distinct clean exit beacons stored in Local