DHCP regression on 2009-06

Fixed the DHCP/BOOTP/RARP regression introduced in u-boot-2009.06
by initializing our IP addr to 0 in order to accept any IP addr
assigned to us by the DHCP/BOOTP/RARP server.

Ack-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: Michael Zaidman <michael.zaidman@gmail.com>
Signed-off-by: Ben Warren <biggerbadderben@gmail.com>

net/net.c

@@ -394,17 +394,20 @@ restart:
 #if defined(CONFIG_CMD_DHCP)
 		case DHCP:
 			BootpTry = 0;
+			NetOurIP = 0;
 			DhcpRequest();		/* Basically same as BOOTP */
 			break;
 #endif
 
 		case BOOTP:
 			BootpTry = 0;
+			NetOurIP = 0;
 			BootpRequest ();
 			break;
 
 		case RARP:
 			RarpTry = 0;
+			NetOurIP = 0;
 			RarpRequest ();
 			break;
 #if defined(CONFIG_CMD_PING)