Drop unnecessary "throws" clauses in archive code

Noticed by eclipse.

Change-Id: I730b290556066038efeaf2436de95415b175f351

org.eclipse.jgit.archive/src/org/eclipse/jgit/archive/FormatActivator.java

  * leaks).
  */
 public class FormatActivator implements BundleActivator {
-	public void start(BundleContext context) throws Exception {
+	public void start(BundleContext context) {
 		ArchiveFormats.registerAll();
 	}
 
-	public void stop(BundleContext context) throws Exception {
+	public void stop(BundleContext context) {
 		ArchiveFormats.unregisterAll();
 	}
 }

org.eclipse.jgit/src/org/eclipse/jgit/api/ArchiveCommand.java

 		setCallable(false);
 	}
 
-	private <T extends Closeable>
-	OutputStream writeArchive(Format<T> fmt) throws GitAPIException {
+	private <T extends Closeable> OutputStream writeArchive(Format<T> fmt) {
 		final TreeWalk walk = new TreeWalk(repo);
 		try {
 			final T outa = fmt.createArchiveOutputStream(out);