Disable attach of repackaged artifact

This commit allows to generate the packaged artifact only locally by
adding a new `attach` property. If `attach` is set to `false` explicitly,
only the main artifact is installed/deployed.

Closes gh-5258

spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/Repackager.java

@@ -37,6 +37,7 @@ import org.springframework.lang.UsesJava8;
  *
  * @author Phillip Webb
  * @author Andy Wilkinson
+ * @author Stephane Nicoll
  */
 public class Repackager {
 
@@ -140,8 +141,7 @@ public class Repackager {
 		destination = destination.getAbsoluteFile();
 		File workingSource = this.source;
 		if (this.source.equals(destination)) {
-			workingSource = new File(this.source.getParentFile(),
-					this.source.getName() + ".original");
+			workingSource = getBackupFile();
 			workingSource.delete();
 			renameFile(this.source, workingSource);
 		}
@@ -162,6 +162,15 @@ public class Repackager {
 		}
 	}
 
+	/**
+	 * Return the {@link File} to use to backup the original source.
+	 * @return the file to use to backup the original source
+	 */
+	public File getBackupFile() {
+		return new File(this.source.getParentFile(),
+			this.source.getName() + ".original");
+	}
+
 	private boolean alreadyRepackaged() throws IOException {
 		JarFile jarFile = new JarFile(this.source);
 		try {