udhcp: slight shrink

udhcp: slight shrink
udhcpd_main                                         1171    1208     +37
udhcpc_main                                         2363    2387     +24
dhcprelay_main                                      1145    1146      +1
dhcprelay_stopflag                                     4       1      -3
dhcprelay_signal_handler                              11       8      -3
client_background                                     46      42      -4
udhcp_read_interface                                 230     211     -19
udhcp_make_pidfile                                    76       -     -76
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 3/4 up/down: 62/-105)           Total: -43 bytes
   text    data     bss     dec     hex filename
 770052    1096   11228  782376   bf028 busybox_old
 769980    1096   11228  782304   befe0 busybox_unstripped