Don't use repo system for standalone director

tycho-p2-director-plugin/src/main/java/org/eclipse/tycho/plugins/p2/director/runtime/StandaloneDirectorRuntimeFactory.java

@@ -17,9 +17,9 @@
 import java.util.Arrays;
 
 import org.apache.maven.artifact.Artifact;
+import org.apache.maven.artifact.DefaultArtifact;
 import org.apache.maven.artifact.repository.ArtifactRepository;
 import org.apache.maven.plugin.MojoExecutionException;
-import org.apache.maven.repository.RepositorySystem;
 import org.codehaus.plexus.component.annotations.Component;
 import org.codehaus.plexus.component.annotations.Requirement;
 import org.codehaus.plexus.logging.Logger;
@@ -31,9 +31,6 @@
 @Component(role = StandaloneDirectorRuntimeFactory.class)
 public class StandaloneDirectorRuntimeFactory {
 
-    @Requirement
-    private RepositorySystem repositorySystem;
-
     @Requirement
     DirectorRuntime bootstrapDirector;
 
@@ -80,8 +77,8 @@ private void installStandaloneDirector(File installLocation, ArtifactRepository
 
     private File getDirectorRepositoryZip(ArtifactRepository localMavenRepository) {
         // this artifact is a dependency of the Mojo, so we expect it in the local Maven repo
-        Artifact artifact = repositorySystem.createArtifact("org.eclipse.tycho", "tycho-bundles-external", "2.7.5",
-                "eclipse-repository");
+        Artifact artifact = new DefaultArtifact("org.eclipse.tycho", "tycho-bundles-external", "2.7.5", null, "zip",
+                null, null);
         return new File(localMavenRepository.getBasedir(), localMavenRepository.pathOf(artifact));
     }
 }