Add missing @since tags

Change-Id: I27207bafe0ce31caab25ab9c0be1f22adf151783
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

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

 	/** The "update" key */
 	public static final String CONFIG_KEY_UPDATE = "update";
 
-	/** The "update" key */
+	/**
+	 * The "ignore" key
+	 * @since 3.6
+	 */
 	public static final String CONFIG_KEY_IGNORE = "ignore";
 
 	/** The "compression" key */

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

 	/**
 	 * @param mode
 	 *            defines how modifications in submodules are treated
+	 * @since 3.6
 	 */
 	public void setIgnoreSubmoduleMode(IgnoreSubmoduleMode mode) {
 		this.ignoreSubmoduleMode = mode;
 
 	/**
 	 * A factory to producing WorkingTreeIterators
+	 * @since 3.6
 	 */
 	public interface WorkingTreeIteratorFactory {
 		/**
 	 * Allows higher layers to set the factory for WorkingTreeIterators.
 	 *
 	 * @param wTreeIt
+	 * @since 3.6
 	 */
 	public void setWorkingTreeItFactory(WorkingTreeIteratorFactory wTreeIt) {
 		this.wTreeIt = wTreeIt;