Reduce visibility of DirCacheCheckout.checkValidPath()

This was deprecated and should only be used by DirCacheCheckout and
friends. Other classes should use SystemReader.checkPath() instead.

Change-Id: I37cf753b1f081602dee9f0f47979eff39d735f92
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheCheckout.java

@@ -1284,10 +1284,8 @@ public class DirCacheCheckout {
 	 * @throws InvalidPathException
 	 *             if the path is invalid
 	 * @since 3.3
-	 * @deprecated Use {@link SystemReader#checkPath(String)}.
 	 */
-	@Deprecated
-	public static void checkValidPath(String path) throws InvalidPathException {
+	static void checkValidPath(String path) throws InvalidPathException {
 		try {
 			SystemReader.getInstance().checkPath(path);
 		} catch (CorruptObjectException e) {