updated cosync storage schema

Author: tolacambo

CosyncStorage/React-Native/CosyncStorageSample/config/Schema.js

@@ -33,10 +33,9 @@ exports.CosyncAsset = {
         "_partition":{ "type": "string", "indexed": true }, 
         "uid":{ "type": "string", "indexed": true },  
         "sessionId":{ "type": "string", "indexed": true},
-        "assetPartition":{ "type": "string", "indexed": true },
-        "filePath": { "type": "string", "default": "" },
         "path":{ "type": "string", "default": ""},
-        "expirationHours": { "type": "double", "default": 24},
+        "expirationHours": { "type": "double", "default": 24}, 
+        "expiration":  { "type": "date", "optional": true},
         "contentType":{ "type": "string", "optional": true}, 
         "size":{ "type": "int", "optional": true, "indexed": true },
         "duration":{ "type": "double", "optional": true },