BUG#34687 Error in bin-log after shutdown restart binlog was not closed properly

While reading a binary log that is being used by a master or was not properly
closed, most likely due to a crash, the following warning message is being
printed out: "Warning: this binlog was not closed properly. Most probably mysqld
crashed writing it.". This was scaring our users as the message was not taking
into account the possibility of the file is being just used by the master.

To avoid unnecessarily scaring our users, we replace the original message by the
following one: Warning: "this binlog is either is use or was not closed properly.".

sql/log_event.cc

@@ -2257,8 +2257,8 @@ void Start_log_event_v3::print(FILE* file, PRINT_EVENT_INFO* print_event_info)
       fprintf(file," at startup");
     fputc('\n', file);
     if (flags & LOG_EVENT_BINLOG_IN_USE_F)
-      fprintf(file, "# Warning: this binlog was not closed properly. "
-              "Most probably mysqld crashed writing it.\n");
+      fprintf(file, "# Warning: this binlog is either in use or was not " 
+                    "closed properly.\n");
   }
   if (!artificial_event && created)
   {