bug fix - SD_SIGN can not be null

src/main/java/com/common/toolbox/app_utils/RequestHandler.java

@@ -80,9 +80,11 @@ public class RequestHandler {
         if (requestBuilder != null) {
             try {
                 String sign = getHeaderSignature();
+                if (headers.get(SD_SIGN) != null && headers.get(DEVICE_SIGN) != null) {
                     requestBuilder.addHeader("X-SD-SIGN", headers.get(SD_SIGN)) //SD卡指纹
-                        .addHeader("X-DEVICE-SIGN", headers.get(DEVICE_SIGN)) //设备指纹
-                        .addHeader("X-SDK-VERSION", String.valueOf(Build.VERSION.SDK_INT)) //Android SDK 版本
+                            .addHeader("X-DEVICE-SIGN", headers.get(DEVICE_SIGN)); //设备指纹
+                }
+                requestBuilder.addHeader("X-SDK-VERSION", String.valueOf(Build.VERSION.SDK_INT)) //Android SDK 版本
                         .addHeader("X-HAEDWARE-INFO", URLEncoder.encode(DeviceInfo.getHardwareInfo(), "UTF-8")) //硬件信息
                         .addHeader("X-APP-SIGN", sign) // Header 签名
                         .addHeader("X-APP-RANDOM", getRandom());// 随机串