Bug#16180 Setting SQL_LOG_OFF without SUPER privilege is silently ignored

mysql-test/r/grant2.result:
  Added results for bug#16180
mysql-test/t/grant2.test:
  Added test for bug# 16180
sql/set_var.cc:
  Verify user has appropiate rights before setting the sql_log_off system variable.

mysql-test/r/grant2.result

@@ -143,3 +143,13 @@ flush privileges;
 drop user mysqltest_3@host3;
 drop user mysqltest_1@host1, mysqltest_2@host2, mysqltest_4@host4,
 mysqltest_5@host5, mysqltest_6@host6, mysqltest_7@host7;
+create database mysqltest_1;
+grant select, insert, update on `mysqltest\_1`.* to mysqltest_1@localhost;
+set sql_log_off = 1;
+ERROR HY000: Access denied; you need the SUPER privilege for this operation
+set sql_log_bin = 0;
+ERROR HY000: Access denied; you need the SUPER privilege for this operation
+delete from mysql.user where user like 'mysqltest\_1';
+delete from mysql.db where user like 'mysqltest\_1';
+drop database mysqltest_1;
+flush privileges;

mysql-test/t/grant2.test

@@ -238,5 +238,22 @@ connect (con9,127.0.0.1,root,,test,$MASTER_MYPORT,);
 disconnect con9;
 connection default;
 
+#
+# Bug# 16180 - Setting SQL_LOG_OFF without SUPER privilege is silently ignored
+#
+create database mysqltest_1;
+grant select, insert, update on `mysqltest\_1`.* to mysqltest_1@localhost;
+connect (con10,localhost,mysqltest_1,,);
+connection con10;
+--error 1227
+set sql_log_off = 1;
+--error 1227
+set sql_log_bin = 0;
+disconnect con10;
+connection default;
+delete from mysql.user where user like 'mysqltest\_1';
+delete from mysql.db where user like 'mysqltest\_1';
+drop database mysqltest_1;
+flush privileges;
 
 # End of 4.1 tests

sql/set_var.cc

@@ -423,7 +423,8 @@ static sys_var_thd_bit	sys_sql_big_tables("sql_big_tables", 0,
 static sys_var_thd_bit	sys_big_selects("sql_big_selects", 0,
 					set_option_bit,
 					OPTION_BIG_SELECTS);
-static sys_var_thd_bit	sys_log_off("sql_log_off", 0,
+static sys_var_thd_bit	sys_log_off("sql_log_off",
+				    check_log_update,
 				    set_option_bit,
 				    OPTION_LOG_OFF);
 static sys_var_thd_bit	sys_log_update("sql_log_update",