attach assembly plugin explicitly to package phase

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/companions/extras/trunk@1531820 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/pom.xml b/pom.xml
index 0016a9d..6620dda 100644
--- a/pom.xml
+++ b/pom.xml
@@ -254,6 +254,15 @@
           <descriptor>src/main/assembly/bin.xml</descriptor>
           <descriptor>src/main/assembly/src.xml</descriptor>
         </configuration>
+        <executions>
+          <execution>
+            <id>make-assembly</id>
+            <phase>package</phase>
+            <goals>
+              <goal>single</goal>
+            </goals>
+          </execution>
+        </executions>
       </plugin>
     </plugins>
   </build>