fixed command line used to build DM

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@987876 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/dependencymanager/samples.annotation/README b/dependencymanager/samples.annotation/README
index f033e88..38e855f 100644
--- a/dependencymanager/samples.annotation/README
+++ b/dependencymanager/samples.annotation/README
@@ -36,7 +36,7 @@
 
      svn checkout http://svn.apache.org/repos/asf/felix/trunk/dependencymanager dependencymanager
      cd dependencymanager
-     mvn -Dmaven.test.skip=true install
+     mvn -Dpackaging=plugins -Dmaven.test.skip=true install
 
   - install the DM bundles into the fwk