gnt-job auto-completion: suggest "all" too

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>

scripts/gnt-job

@@ -365,7 +365,7 @@ commands = {
     "<job-id> [<job-id> ...]", "Archive specified jobs"),
   'autoarchive': (
     AutoArchiveJobs,
-    [ArgSuggest(min=1, max=1, choices=["1d", "1w", "4w"])],
+    [ArgSuggest(min=1, max=1, choices=["1d", "1w", "4w", "all"])],
     [],
     "<age>", "Auto archive jobs older than the given age"),
   'cancel': (