Revert "Update the fail/report criticality for revapi"

This reverts commit 8603e6d.

A check of the source code for revapi 0.15 shows that the
value of reportCriticality is not used. Only the value of
reportSeverity is used in the ReportMojo.

pom.xml

@@ -666,6 +666,10 @@ This is avoided by creating an empty directory when svn is not available.
                   </roots>
                 </configurationFile>
               </analysisConfigurationFiles>
+              <!-- Note: Property 'reportSeverity' is deprecated but newer 'reportCriticality'
+                   does work as documented. -->
+              <reportSeverity>equivalent</reportSeverity>
+              <reportCriticality>allowed</reportCriticality>
             </configuration>
             <reportSets>
               <reportSet>