BUG#28372 mysqldump test case fails with binlog disabled

mysql-test/t/mysqldump.test:
  BUG#28372 don't run this test case if binlog is disabled

mysql-test/t/mysqldump.test

 # Embedded server doesn't support external clients
 --source include/not_embedded.inc
 
+# Binlog is required
+--source include/have_log_bin.inc
+
 --disable_warnings
 DROP TABLE IF EXISTS t1, `"t"1`, t1aa, t2, t2aa, t3;
 drop database if exists mysqldump_test_db;