Add a --limit parameter to list operations

In v2, we use the link header during paginations to know when there are
more images available in the server that could be returned in the same
request. This way, it's possible to iterate over the generator returned
by list and consume the images in the server.

However, it's currently not possible to tell glanceclient the exact
number of images we want, which basically means that it'll *always* go
through the whole list of images in the server unless the limit is
implemented by the consumer.

DocImpact
Change-Id: I9f65a40d4eafda6320e5c7d94d03fcd1bbc93e33
Closes-bug: #1415035

glanceclient/v2/shell.py

@@ -107,6 +107,8 @@ def do_image_update(gc, args):
     utils.print_image(image)
 
 
+@utils.arg('--limit', metavar='<LIMIT>', default=None, type=int,
+           help='Maximum number of images to get.')
 @utils.arg('--page-size', metavar='<SIZE>', default=None, type=int,
            help='Number of images to request in each paginated request.')
 @utils.arg('--visibility', metavar='<VISIBILITY>',
@@ -135,6 +137,8 @@ def do_image_list(gc, args):
     filters = dict([item for item in filter_items if item[1] is not None])
 
     kwargs = {'filters': filters}
+    if args.limit is not None:
+        kwargs['limit'] = args.page_size
     if args.page_size is not None:
         kwargs['page_size'] = args.page_size