making sure that JDK6 is required for building Hudson

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@11332 71c3de6d-444a-0410-be80-ed276b4c234a

core/pom.xml

@@ -13,7 +13,7 @@
 
   <build>
     <plugins>
-      <!--plugin>
+      <plugin>
         <artifactId>maven-enforcer-plugin</artifactId>
         <executions>
           <execution>
@@ -22,15 +22,15 @@
             </goals>
             <configuration>
               <rules>
-          - There is a bug in JDK 1.5's compiler therefore need to compile with 1.6 -
-          <requireJavaVersion>
-            <version>[1.6.0,]</version>
-          </requireJavaVersion>
+                <!-- There is a bug in JDK 1.5's compiler therefore need to compile with 1.6 -->
+                <requireJavaVersion>
+                  <version>[1.6.0,]</version>
+                </requireJavaVersion>
               </rules>
             </configuration>
           </execution>
         </executions>
-      </plugin-->
+      </plugin>
       <plugin>
         <groupId>org.kohsuke.stapler</groupId>
         <artifactId>maven-stapler-plugin</artifactId>