bugfix: check 0 sized file

opencv-motion-detect/deployment/version.json

 {
-    "b1.0.0": {
+    "activeIdx": -1,
+    "bundles": [
+        {
+            "releaseId": "aabbcc",
+            "updateTime": 123,
             "evcloudsvc": {
                 "url": "",
                 "version": "0.1.1",
@@ -36,5 +40,6 @@
                 "updateTime": 123     
             }
         }
+    ]
 }