added optional attribute to dependency artifact

git-svn-id: https://svn.apache.org/repos/asf/maven/shared/trunk@1350763 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/main/java/org/apache/maven/shared/dependency/graph/internal/Maven3DependencyNode.java b/src/main/java/org/apache/maven/shared/dependency/graph/internal/Maven3DependencyNode.java
index 48ef43b..a00ed77 100644
--- a/src/main/java/org/apache/maven/shared/dependency/graph/internal/Maven3DependencyNode.java
+++ b/src/main/java/org/apache/maven/shared/dependency/graph/internal/Maven3DependencyNode.java
@@ -59,7 +59,8 @@
             Artifact tmpArtifact =
                 factory.createDependencyArtifact( art.getGroupId(), art.getArtifactId(),
                                                   VersionRange.createFromVersion( art.getVersion() ),
-                                                  art.getExtension(), art.getClassifier(), dep.getScope() );
+                                                  art.getExtension(), art.getClassifier(), dep.getScope(),
+                                                  dep.isOptional() );
 
             if ( !filter.include( tmpArtifact ) )
             {