FS: Document readpipe()'s encoding parameter

Change-Id: I36f0edf0f9d0bfa26448e25355c6d78dea524079
Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>

org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java

@@ -403,6 +403,7 @@ public abstract class FS {
 	 * @param command
 	 *            as component array
 	 * @param encoding
+	 *            to be used to parse the command's output
 	 * @return the one-line output of the command
 	 */
 	protected static String readPipe(File dir, String[] command, String encoding) {