modified mothed of send connection to a waiting process

The old mothed : the emysql_conn_mgr process send a connection to waiting process ,but if the process has been dead , the connection will not return never. 
So, when emysql_conn_mgr process send a connection to one waiting process , should check the process if alive. If the process has been dead (beacuse timeout or other reason, wait timeout will remove self from the wait queue but other reason will not), emysql_conn_mgr should not send connection.