udhcpc: remove code which requires server ID to be on local network

This reverts "udhcpc: paranoia when using kernel UDP mode
for sending renew: server ID may be bogus".

Users complain that they do have servers behind routers
(with DHCP relays).

function                                             old     new   delta
send_packet                                          168     166      -2
bcast_or_ucast                                        25      23      -2
udhcp_send_kernel_packet                             301     295      -6
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-10)             Total: -10 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/networking/udhcp/packet.c b/networking/udhcp/packet.c
index fc2bb54..ff16904 100644
--- a/networking/udhcp/packet.c
+++ b/networking/udhcp/packet.c
@@ -189,8 +189,7 @@
 /* Let the kernel do all the work for packet generation */
 int FAST_FUNC udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
 		uint32_t source_nip, int source_port,
-		uint32_t dest_nip, int dest_port,
-		int send_flags)
+		uint32_t dest_nip, int dest_port)
 {
 	struct sockaddr_in sa;
 	unsigned padding;
@@ -227,8 +226,8 @@
 	padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(dhcp_pkt->options);
 	if (padding > DHCP_SIZE - 300)
 		padding = DHCP_SIZE - 300;
-	result = send(fd, dhcp_pkt, DHCP_SIZE - padding, send_flags);
-	msg = "send";
+	result = safe_write(fd, dhcp_pkt, DHCP_SIZE - padding);
+	msg = "write";
  ret_close:
 	close(fd);
 	if (result < 0) {