Bug #25228: rpl_relayspace.test fails on powermacg5, vm-win2003-32-a

A test case was waiting for a fixed number of seconds for a specific 
state of the slave IO thread to take place.
Fixed by waiting in a loop for that specific thread state instead 
(or timeout).

mysql-test/t/rpl_relayspace.test

@@ -14,6 +14,22 @@ connection slave;
 reset slave;
 start slave io_thread;
 # Give the I/O thread time to block.
+let $run= 1;
+let $counter= 300;
+while ($run)
+{
+  let $io_state= query_get_value("SHOW SLAVE STATUS", Slave_IO_State, 1);
+  if (`SELECT '$io_state' = 'Waiting for the slave SQL thread to free enough relay log space'`){
+    let $run= 0;
+  }
+  sleep 0.1;
+  if (!$counter){
+   --echo "Failed while waiting for slave IO thread block"
+   SHOW SLAVE STATUS;
+   exit;
+  }
+  dec $counter;
+}
 sleep 2;
 # A bug caused the I/O thread to refuse stopping.
 stop slave io_thread;