Issue here is that log messages with zero error ID are logged
from test plugins and components. As part of this patch, error
logging calls in the following plugins/components are changed
to log error messages with error IDs :-

component_log_sink_test
pfs_example_plugin_employee
replication_observers_example
test_plugin_server
test_session_attach
test_session_detach
test_session_in_thd
test_session_info
test_sql_2_sessions
test_sql_9_sessions
test_sql_all_col_types
test_sql_cmds_1
test_sql_commit
test_sql_complex
test_sql_errors
test_sql_lock
test_sql_processlist
test_sql_replication
test_sql_shutdown
test_sql_sqlmode
test_sql_stmt
test_sql_stored_procedures_functions
test_sql_views_triggers
test_services
test_services_threaded
test_services_plugin_registry
test_x_sessions_deinit
test_x_sessions_init

The patch removes all instances of the my_plugin_log_message()
call from server code and also does the following :-
- Add error-ID's to a couple of error messages using client
  error codes in log_filter_dragnet.
- It also adds a message in xplugin which uses a zero error
  code.