Use Builder to evaluate the bsn and version of the project

Currently if the version contains an evaluated expression this is used
as is and maven complains about that.

This now use the ProjectBuilder to evaluate the actual version and bsn.

(cherry picked from commit 04710cf)

tycho-build/src/main/java/org/eclipse/tycho/build/bnd/BndProjectMapping.java

@@ -35,6 +35,7 @@
 import org.sonatype.maven.polyglot.mapping.Mapping;
 
 import aQute.bnd.build.Project;
+import aQute.bnd.build.ProjectBuilder;
 import aQute.bnd.build.Workspace;
 
 @Component(role = Mapping.class, hint = "bnd")
@@ -106,16 +107,18 @@ protected void initModel(Model model, Reader artifactReader, Path artifactFile)
 			if (g != null) {
 				model.setGroupId(g);
 			}
-			if (a == null) {
-				model.setArtifactId(project.getName());
-			} else {
-				model.setArtifactId(a);
-			}
-			if (v == null) {
-				model.setVersion(project.getBundleVersion());
-			} else {
-				model.setVersion(v);
+			if (a == null || v == null) {
+				try (ProjectBuilder builder = createBuilder(project)) {
+					if (a == null) {
+						a = builder.getBsn();
+					}
+					if (v == null) {
+						v = builder.getVersion();
+					}
+				}
 			}
+			model.setArtifactId(a);
+			model.setVersion(v);
 			Build build = getBuild(model);
 			build.setDirectory(path(project.getTarget()));
 			build.setOutputDirectory(path(project.getSrcOutput()));
@@ -124,7 +127,6 @@ protected void initModel(Model model, Reader artifactReader, Path artifactFile)
 			File src = project.getSrc();
 			build.setSourceDirectory(path(src));
 			build.setTestSourceDirectory(path(project.getTestSrc()));
-			model.setVersion(project.getBundleVersion());
 			Plugin bndPlugin = getPlugin(model, TYCHO_GROUP_ID, TYCHO_BND_PLUGIN);
 			bndPlugin.setExtensions(true);
 			bndPlugin.setVersion(TychoVersion.getTychoVersion());
@@ -165,6 +167,14 @@ protected void initModel(Model model, Reader artifactReader, Path artifactFile)
 
 	}
 
+	private static ProjectBuilder createBuilder(Project project) throws Exception {
+		ProjectBuilder builder = new ProjectBuilder(project);
+		builder.setBase(project.getBase());
+		builder.use(project);
+		builder.setFailOk(true);
+		return builder;
+	}
+
 	private static String path(File file) throws Exception {
 		if (file != null) {
 			return file.getAbsolutePath();