udhcpc: do not use -t NUM for counting "select" packets, use 3

Otherwise, "-t 0" usage may end up sending them forever
if server does not respond.

function                                             old     new   delta
udhcpc_main                                         2846    2836     -10

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
1 file changed