move reporting plugin version to a property

git-svn-id: https://svn.apache.org/repos/asf/archiva/redback/redback-components/trunk@1378524 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/pom.xml b/pom.xml
index 412da5e..b795bde 100644
--- a/pom.xml
+++ b/pom.xml
@@ -273,7 +273,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-project-info-reports-plugin</artifactId>
-        <version>2.5</version>
+        <version>${maven-project-info-reports-plugin.version}</version>
       </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>