DescribeCommand: Consistenly omit the default value

Omit the default value of "false" for "useTags" like already done for
"longDesc".

Change-Id: I25aaacae028fc8cf27f4040ba45fe79609318aa1
Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>

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

@@ -109,7 +109,7 @@ public class DescribeCommand extends GitCommand<String> {
 	/**
 	 * Whether to use all tags (incl. lightweight) or not.
 	 */
-	private boolean useTags = false;
+	private boolean useTags;
 
 	/**
 	 * Constructor for DescribeCommand.