[Satellite6] ImportError: cannot import name Repo while upgrading Satellite 6.1.9 to Satellite 6.2

Issue

• Upgrading Satellite 6.1.9 to Satellite 6.2.0 failed

# satellite-installer --scenario satellite --upgrade

Beginning database migrations.
Upgrade step migrate_pulp failed
cannot import name Repo
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/pulp/server/db/manage.py", line 193, in main
    return _auto_manage_db(options)
  File "/usr/lib/python2.7/site-packages/pulp/server/db/manage.py", line 256, in _auto_manage_db
    migrate_database(options)
  File "/usr/lib/python2.7/site-packages/pulp/server/db/manage.py", line 65, in migrate_database
    migration_packages = models.get_migration_packages()
  File "/usr/lib/python2.7/site-packages/pulp/server/db/migrate/models.py", line 323, in get_migration_packages
    migration_packages = [MigrationPackage(pulp.server.db.migrations)]
  File "/usr/lib/python2.7/site-packages/pulp/server/db/migrate/models.py", line 168, in __init__
    available_versions = self.available_versions
  File "/usr/lib/python2.7/site-packages/pulp/server/db/migrate/models.py", line 198, in available_versions
    migrations = self.migrations
  File "/usr/lib/python2.7/site-packages/pulp/server/db/migrate/models.py", line 227, in migrations
    migration_modules.append(MigrationModule(module_name))
  File "/usr/lib/python2.7/site-packages/pulp/server/db/migrate/models.py", line 90, in __init__
    self._module = _import_all_the_way(python_module_name)
  File "/usr/lib/python2.7/site-packages/pulp/server/db/migrate/models.py", line 344, in _import_all_the_way
    module = __import__(module_string)
  File "/usr/lib/python2.7/site-packages/pulp/server/db/migrations/0004_content_unit_counts.py", line 14, in <module>
    from pulp.server.db.model.repository import Repo
ImportError: cannot import name Repo