Make clear method on StoredConfig public

EGit needs this to be able to revert unsaved changes.

Change-Id: I50cc8056aaff47fef6080970866962e3eb634e29
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/src/org/eclipse/jgit/lib/StoredConfig.java

@@ -87,4 +87,9 @@ public abstract class StoredConfig extends Config {
 	 *             the configuration could not be written.
 	 */
 	public abstract void save() throws IOException;
+
+	@Override
+	public void clear() {
+		super.clear();
+	}
 }