ERP5Type: fix logger "name" when logging warnings

Instead of using an always-different logger name which confuses log
analytics system, use the warning category as logger name (or what zLOG.LOG
calls "subsystem")
5 jobs for fix/warning_logger_format in 0 seconds
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-TestRunner2

00:54:08

failed ERP5.UnitTest-TestRunner2

04:52:33

passed ERP5.CodingStyleTest-TestRunner2

00:35:57

failed ERP5.CodingStyleTest-TestRunner2

05:13:38

failed ERP5.UnitTest-TestRunner2

04:08:21