[autotest] Manage shards with atest

This adds functionality to list, create and delete shards to atest.

BUG=None
TEST=Ran suites, manual test of create/list/delete.

Change-Id: I0771d0c1b46c7c6890819822204f42ac2211b104
Reviewed-on: https://chromium-review.googlesource.com/218295
Tested-by: Jakob Jülich <[email protected]>
Reviewed-by: Prashanth B <[email protected]>
Commit-Queue: Jakob Jülich <[email protected]>
diff --git a/cli/topic_common.py b/cli/topic_common.py
index d2fd891..c44f67d 100644
--- a/cli/topic_common.py
+++ b/cli/topic_common.py
@@ -162,7 +162,7 @@
                  filename_option='', use_leftover=False):
         """Object keeping track of the parsing options that will
         make up the content of the atest attribute:
-        atttribute_name: the atest attribute name to populate    (label)
+        attribute_name: the atest attribute name to populate    (label)
         inline_option: the option containing the items           (--label)
         filename_option: the option containing the filename      (--blist)
         use_leftover: whether to add the leftover arguments or not."""
@@ -241,7 +241,7 @@
     Should only be instantiated by itself for usage
     references, otherwise, the <topic> objects should
     be used."""
-    msg_topic = "[acl|host|job|label|atomicgroup|test|user]"
+    msg_topic = "[acl|host|job|label|shard|atomicgroup|test|user]"
     usage_action = "[action]"
     msg_items = ''