ENG-2942: Send num shards parameter to master from yb-ctl.

Summary:
If that is missing, then create table can use unexpected values on the server (catalog_manager).

Test Plan:
`~/code/yugabyte/bin/yb-ctl --num_shards_per_tserver 8 create` and ensured master process also gets the parameter passed in.

Reviewers: bogdan, hector

Reviewed By: hector

Subscribers: ybase

Differential Revision: https://phabricator.dev.yugabyte.com/D4355

bin/yb-ctl

@@ -403,6 +403,7 @@ class ClusterControl:
     def get_master_only_flags(self, daemon_id):
         command_list = [
             "--replication_factor={}".format(self.options.replication_factor),
+            "--yb_num_shards_per_tserver {}".format(self.options.num_shards_per_tserver)
         ]
 
         if not self.options.is_shell_master: