Add missing @since tags

Change-Id: I16d82499d7d000096de6bd4bd08e406073557162
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

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

@@ -564,6 +564,7 @@ public class CheckoutCommand extends GitCommand<Ref> {
 	 *            if <code>true</code> a orphan branch will be created as part
 	 *            of the checkout to the specified start point
 	 * @return this instance
+	 * @since 3.3
 	 */
 	public CheckoutCommand setOrphan(boolean orphan) {
 		checkCallable();

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

@@ -287,7 +287,11 @@ public final class Constants {
 	/** The environment variable that contains the commiter's email */
 	public static final String GIT_COMMITTER_EMAIL_KEY = "GIT_COMMITTER_EMAIL";
 
-	/** The environment variable that blocks use of the system config file */
+	/**
+	 * The environment variable that blocks use of the system config file
+	 *
+	 * @since 3.3
+	 */
 	public static final String GIT_CONFIG_NOSYSTEM_KEY = "GIT_CONFIG_NOSYSTEM";
 
 	/**