Fix SOVRN's ad example. (ampproject#6396)

examples/ads.amp.html

@@ -146,7 +146,7 @@ <h2>Ad networks in <span class="broken">red color</span> have broken examples, p
     <a href="#smartadserver">SmartAdServer</a> |
     <a href="#smartclip">smartclip</a> |
     <a href="#sortable">Sortable ad</a> |
-    <a href="#sovrn" class="broken">SOVRN</a> |
+    <a href="#sovrn">SOVRN</a> |
     <a href="#taboola">Taboola</a> |
     <a href="#teads">Teads</a> |
     <a href="#triplelift">TripleLift</a> |
@@ -1018,8 +1018,7 @@ <h2 id="sortable">Sortable ad</h2>
     <div fallback></div>
   </amp-ad>
 
-  <h2 id="sovrn" class="broken">SOVRN</h2>
-  <a href="https://github.com/ampproject/amphtml/issues/4614">Issue on GitHub</a><br>
+  <h2 id="sovrn">SOVRN</h2>
   <amp-ad width=300 height=250
       type="sovrn"
       data-width="300"
@@ -1028,7 +1027,7 @@ <h2 id="sovrn" class="broken">SOVRN</h2>
       data-iid="informerIDgoeshere"
       data-aid="affiliateIDgoeshere"
       data-testFlag="true"
-      data-z="342521">
+      data-z="393900"><!-- this ID is only whitelisted for localhost:8000 and http://amphtml-nightly.herokuapp.com-->
     <div placeholder></div>
     <div fallback></div>
   </amp-ad>