Drop Clirr property since commons-parent has replaced Clirr with
JApiCmp.
diff --git a/pom.xml b/pom.xml
index 962d1fc..f9bcb1b 100644
--- a/pom.xml
+++ b/pom.xml
@@ -347,7 +347,6 @@
 
     <japicmp.skip>false</japicmp.skip>
     <spotbugs.skip>false</spotbugs.skip>
-    <clirr.skip>true</clirr.skip>
     <findbugs.skip>true</findbugs.skip>
     <surefire.argline></surefire.argline>
   </properties>