Re-apply FELIX-843 patch to latest BND code

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@738794 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/bundleplugin/src/main/java/aQute/lib/osgi/Builder.java b/bundleplugin/src/main/java/aQute/lib/osgi/Builder.java
index 393e7ee..7c631ae 100644
--- a/bundleplugin/src/main/java/aQute/lib/osgi/Builder.java
+++ b/bundleplugin/src/main/java/aQute/lib/osgi/Builder.java
@@ -266,7 +266,7 @@
             // Private-Package
             Map<String, Map<String, String>> filtered = merge(
                     CONDITIONAL_PACKAGE, conditionals, imports,
-                    new HashSet<String>());
+                    new HashSet<String>(), null);
 
             // Imports can also specify a private import. These
             // packages must also be copied to the bundle