Exception thrown when running df-db with Python3

[Shachar Snapiri]

Running df-db dump with Python3 and etcd DB throws an exeption:

Traceback (most recent call last):
  File "/usr/local/bin/df-db", line 10, in <module>
    sys.exit(main())
  File "/opt/dragonflow/dragonflow/cli/df_db.py", line 497, in main
    args.handle(args)
  File "/opt/dragonflow/dragonflow/cli/df_db.py", line 345, in handle
    dump_tables(format_)
  File "/opt/dragonflow/dragonflow/cli/df_db.py", line 148, in dump_tables
    print_whole_table(table)
  File "/opt/dragonflow/dragonflow/cli/df_db.py", line 113, in print_whole_table
    for key in keys]
  File "/opt/dragonflow/dragonflow/cli/df_db.py", line 113, in <listcomp>
    for key in keys]
  File "/opt/dragonflow/dragonflow/db/drivers/etcd_db_driver.py", line 117, in get_key
    return self._get_key(self._make_key(table, key), key)
  File "/opt/dragonflow/dragonflow/db/drivers/etcd_db_driver.py", line 123, in _get_key
    raise df_exceptions.DBKeyNotFound(key=key)
dragonflow.common.exceptions.DBKeyNotFound: DB Key not found, key=b'lport'

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/624888
Committed: https://git.openstack.org/cgit/openstack/dragonflow/commit/?id=7c4a2970808094c3f66a0d4216d2dc02a5c57ec4
Submitter: Zuul
Branch: master

commit 7c4a2970808094c3f66a0d4216d2dc02a5c57ec4
Author: Shachar Snapiri <email address hidden>
Date: Thu Dec 13 10:18:23 2018 +0200

    Fix exception in df-db under Python3

    Exception is thrown when running df-db dump with Python3

    Change-Id: I8b5b7715a429150f1e12277e066d24c8ea0039a3
    Closes-Bug: #1808295