if no previous successful build, do not show changes section

src/root/build.tt

@@ -184,6 +184,7 @@
 				[% INCLUDE renderBuildSteps type="Failed" %]
 			[% END %]
 
+            [% IF prevSuccessfulBuild %]
             <h2>Changes</h2>
             <br/> 
             <table>
@@ -209,6 +210,7 @@
                     <td>[% INCLUDE renderInputDiff build1=prevSuccessfulBuild , build2=build %]</td>
                 </tr>
             </table>
+            [% END %]
 
 			[% IF build.resultInfo.errormsg && build.resultInfo.buildstatus != 5 %]