Remove final modifier on args4j argument field in RevParse

Args4J does no longer allow to use final fields to reference
arguments or options [1]. Change RevParse to be compatibel with this
change.

[1] 6e11f89d40

See-also: a0558b7094
Signed-off-by: Rüdiger Herrmann <ruediger.herrmann@gmx.de>
Change-Id: I33b233f195c06855d9e094c8c9ba804fbe7b1438

org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/RevParse.java

@@ -68,7 +68,7 @@ class RevParse extends TextBuiltin {
 	boolean verify;
 
 	@Argument(index = 0, metaVar = "metaVar_commitish")
-	private final List<ObjectId> commits = new ArrayList<>();
+	private List<ObjectId> commits = new ArrayList<>();
 
 	@Override
 	protected void run() throws Exception {