bugfix, only add property if the value is not null

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@888320 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/dependencymanager/core/src/main/java/org/apache/felix/dm/impl/dependencies/ResourceDependencyImpl.java b/dependencymanager/core/src/main/java/org/apache/felix/dm/impl/dependencies/ResourceDependencyImpl.java
index c3ede77..b993e97 100644
--- a/dependencymanager/core/src/main/java/org/apache/felix/dm/impl/dependencies/ResourceDependencyImpl.java
+++ b/dependencymanager/core/src/main/java/org/apache/felix/dm/impl/dependencies/ResourceDependencyImpl.java
@@ -80,8 +80,11 @@
 	        }
 	    }
 	    if (needsStarting) {
-	        Properties props = new Properties();
-	        props.setProperty(Resource.FILTER, m_resourceFilter);
+	        Properties props = null;
+	        if (m_resourceFilter != null) {
+	            props = new Properties();
+	            props.setProperty(Resource.FILTER, m_resourceFilter);
+	        }
 	        m_registration = m_context.registerService(ResourceHandler.class.getName(), this, props);
 	    }
 	}