move the attach descriptor to the maven pom since there's no site with the asf pom. Also set the inherited flag to false so it's not run for every child of maven.

git-svn-id: https://svn.apache.org/repos/asf/maven/pom/trunk@1069610 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/pom.xml b/pom.xml
index 15b6d26..e9395ca 100644
--- a/pom.xml
+++ b/pom.xml
@@ -386,19 +386,6 @@
             </plugin>
           </plugins>
         </pluginManagement>
-        <plugins>
-          <plugin>
-            <artifactId>maven-site-plugin</artifactId>
-            <executions>
-              <execution>
-                <id>attach-descriptor</id>
-                <goals>
-                  <goal>attach-descriptor</goal>
-                </goals>
-              </execution>
-            </executions>
-          </plugin>
-        </plugins>
       </build>
     </profile>    
   </profiles>