cubicweb #5491700 source-sync fail with 'Connection' object has no attribute 'close' [resolved]

This is only about development version 3.21.

When trying to manually synchronize data from an external source using the source-sync command, an exception is raised:

cubicweb-ctl source-sync <instance_name> <source_name>
Traceback (most recent call last):
  File "/usr/bin/cubicweb-ctl", line 4, in <module>
    run(sys.argv[1:])
  File "/home/yvote/Yann/ProjetsDev/cubicweb/cubicweb/cwctl.py", line 1139, in run
    CWCTL.run(args)
  File "/usr/lib/python2.7/dist-packages/logilab/common/clcommands.py", line 136, in run
    sys.exit(command.main_run(args, rcfile))
  File "/usr/lib/python2.7/dist-packages/logilab/common/clcommands.py", line 265, in main_run
    self.run(args)
  File "/home/yvote/Yann/ProjetsDev/cubicweb/cubicweb/server/serverctl.py", line 951, in run
    cnx.close()
AttributeError: 'Connection' object has no attribute 'close'

Works fine in 3.20.7.