修复dhcp租期错误的问题

jni/net/DhcpClient.cpp

@@ -375,7 +375,7 @@ bool DhcpClient::start(const char *ip, const char *macaddr, const char *gateway)
 	gateway_ = gateway;
 	record_time_ = get_sec();
 //	lease_ = 60 * 60;    // 1 hour
-	lease_ = 100;    // 100分钟
+	lease_ = 100 * 60;    // 100分钟
 	record_lease_ = 0;
 
 	LOGD("开始请求dhcp，ip == %s", ip);