The combination of --single-transaction and --master-data requires
START TRANSACTION WITH CONSISTENT SNAPSHOT which is available from
mysqld 4.1 on. When trying this against an older server, print
diagnostic, then, if --force is not given, abort.

No test-case given since it would require a mysqld < 4.1.


client/mysqldump.c:
  Bug #30444: 5.0 mysqldump silently allows wrong backup to be taken against a 4.0 database
  
  The combination of --single-transaction and --master-data requires
  START TRANSACTION WITH CONSISTENT SNAPSHOT which is available from
  mysqld 4.1 on. When trying this against an older server, print
  diagnostic, then, if --force is not given, abort.