Bug#28772, added waiting Until_Log_Pos when slave starting with UNTIL clause...

Bug#28772, added waiting Until_Log_Pos when slave starting with UNTIL clause and then waiting stop of slave. 
It helps to avoid issues when slave starts too slowly.

mysql-test/suite/rpl/r/rpl_row_until.result

@@ -150,7 +150,7 @@ Last_SQL_Errno	0
 Last_SQL_Error	
 start slave;
 stop slave;
-start slave until master_log_file='master-bin.000001', master_log_pos=740;
+start slave sql_thread until master_log_file='master-bin.000001', master_log_pos=740;
 SHOW SLAVE STATUS;
 Slave_IO_State	#
 Master_Host	127.0.0.1
@@ -162,7 +162,7 @@ Read_Master_Log_Pos	750
 Relay_Log_File	#
 Relay_Log_Pos	#
 Relay_Master_Log_File	master-bin.000001
-Slave_IO_Running	Yes
+Slave_IO_Running	No
 Slave_SQL_Running	No
 Replicate_Do_DB	
 Replicate_Ignore_DB	
@@ -200,7 +200,7 @@ start slave until relay_log_file='slave-relay-bin.000002';
 ERROR HY000: Incorrect parameter or combination of parameters for START SLAVE UNTIL
 start slave until relay_log_file='slave-relay-bin.000002', master_log_pos=561;
 ERROR HY000: Incorrect parameter or combination of parameters for START SLAVE UNTIL
-start slave sql_thread;
+start slave;
 start slave until master_log_file='master-bin.000001', master_log_pos=740;
 Warnings:
 Note	1254	Slave is already running

mysql-test/suite/rpl/t/rpl_row_until.test

@@ -58,7 +58,10 @@ stop slave;
 --source include/wait_for_slave_to_stop.inc
 
 # this should stop immediately as we are already there
-start slave until master_log_file='master-bin.000001', master_log_pos=740;
+start slave sql_thread until master_log_file='master-bin.000001', master_log_pos=740;
+--let $slave_param= Until_Log_Pos
+--let $slave_param_value= 740
+--source include/wait_for_slave_param.inc
 --source include/wait_for_slave_sql_to_stop.inc
 # here the sql slave thread should be stopped
 --replace_result bin.000005 bin.000004 bin.000006 bin.000004 bin.000007 bin.000004
@@ -76,5 +79,5 @@ start slave until relay_log_file='slave-relay-bin.000002';
 --error 1277
 start slave until relay_log_file='slave-relay-bin.000002', master_log_pos=561;
 # Warning should be given for second command
-start slave sql_thread;
+start slave;
 start slave until master_log_file='master-bin.000001', master_log_pos=740;