Mark NQE histograms as deprecated

These network quality estimator histograms were deprecated earlier,
but they were not correctly marked as deprecated.

Change-Id: Ib1081681cda243e7cd1c27f81ff453899242860f
Bug: 843210
Reviewed-on: https://chromium-review.googlesource.com/1058843Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Tarun Bansal <tbansal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558821}

tools/metrics/histograms/histograms.xml

@@ -58268,6 +58268,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="NQE.RTT" units="ms">
+  <obsolete>
+    Deprecated 01/2018.
+  </obsolete>
   <owner>bengr@chromium.org</owner>
   <owner>tbansal@chromium.org</owner>
   <summary>
@@ -58396,6 +58399,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="NQE.TransportRTT" units="ms">
+  <obsolete>
+    Deprecated 01/2018.
+  </obsolete>
   <owner>bengr@chromium.org</owner>
   <owner>tbansal@chromium.org</owner>
   <summary>
@@ -114691,6 +114697,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <suffix name="Percentile90" label="90th percentile"/>
   <affected-histogram name="NQE.RTT"/>
   <affected-histogram name="NQE.TransportRTT"/>
+  <obsolete>
+    Deprecated 01/2018.
+  </obsolete>
 </histogram_suffixes>
 
 <histogram_suffixes name="NQE.DifferentPercentiles" separator=".">