HBASE-23611 Set version of maven-enforcer-plugin via property (#50)

Signed-off-by: Peter Somogyi <psomogyi@apache.org>
diff --git a/pom.xml b/pom.xml
index 2c726b4..f911c52 100644
--- a/pom.xml
+++ b/pom.xml
@@ -343,12 +343,12 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-enforcer-plugin</artifactId>
-        <version>1.4</version>
+        <version>${enforcer.version}</version>
         <dependencies>
           <dependency>
             <groupId>org.codehaus.mojo</groupId>
             <artifactId>extra-enforcer-rules</artifactId>
-            <version>1.0-beta-6</version>
+            <version>${extra.enforcer.version}</version>
           </dependency>
         </dependencies>
         <!-- version set by parent -->