add_pool() timeout

[jinq0123]

Change a_hello sample to connect to LAN Mysql server:

    emysql:add_pool(hello_pool, [{size,1},
        {host, "192.168.1.2"},
        ...

D:\...\deps\emysql\samples>erl -pa ../ebin -s a_hello run -s init stop -noshell
add_pool...{"init terminating in do_boot",{{nocatch,{failed_to_recv_packet_header,timeout}},[{init,start_it,1,[{file,"init.erl"},{line,1062}]},{init,start_em,1,[{file,"init.erl"},{line,1034}]}]}}

Crash dump is being written to: erl_crash.dump...done
init terminating in do_boot ()

Changing default_timeout to 10s will be OK.

D:\...\deps\emysql\samples>erl -pa ../ebin -s a_hello run -s init
 stop -noshell -emysql default_timeout 10000