Add gerrit.abandon_change command

R=tandrii@chromium.org

Bug: 935715
Change-Id: Ia7b8e2b187b59680270d694b24edf82493d1ed5c
Reviewed-on: https://chromium-review.googlesource.com/c/1487212
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Commit-Queue: Sergiy Belozorov <sergiyb@chromium.org>
diff --git a/gerrit_client.py b/gerrit_client.py
index f2501f1..aecb921 100755
--- a/gerrit_client.py
+++ b/gerrit_client.py
@@ -88,6 +88,19 @@
   write_result(result, opt)
 
 
+@subcommand.usage('')
+def CMDabandon(parser, args):
+  parser.add_option('-c', '--change', type=int, help='change number')
+  parser.add_option('-m', '--message', default='', help='reason for abandoning')
+
+  (opt, args) = parser.parse_args(args)
+  result = gerrit_util.AbandonChange(
+      urlparse.urlparse(opt.host).netloc,
+      opt.change, opt.message)
+  logging.info(result)
+  write_result(result, opt)
+
+
 class OptionParser(optparse.OptionParser):
   """Creates the option parse and add --verbose support."""
   def __init__(self, *args, **kwargs):