Allow to retrieve the error code from the nina module that happend du…

…ring OTA download:

  typedef enum OTA_Error {
    ERR_NO_ERROR = 0,
    ERR_OPEN     = 1,
    ERR_LENGTH   = 2,
    ERR_CRC      = 3,
    ERR_RENAME   = 4,
  };

src/WiFiStorage.h

@@ -58,8 +58,12 @@ class WiFiStorageClass
 		WiFiDrv::downloadFile(url, strlen(url), filename, strlen(filename));
 		return true;
 	}
-    static bool downloadOTA(const char * url) {
-        return (WiFiDrv::downloadOTA(url, strlen(url)) == 0);
+    static bool downloadOTA(const char * url, uint8_t * res_ota_download = NULL) {
+		uint8_t const res = WiFiDrv::downloadOTA(url, strlen(url));
+		if (res_ota_download)
+		  *res_ota_download = res;
+		bool const success = (res == 0);
+        return success;
     }
 
 
@@ -78,8 +82,8 @@ class WiFiStorageClass
     static bool download(String url, String filename) {
     	return download(url.c_str(), filename.c_str());
     }
-    static bool download(String url) {
-        return downloadOTA(url.c_str());
+    static bool download(String url, uint8_t * res_ota_download = NULL) {
+        return downloadOTA(url.c_str(), res_ota_download);
     }
 };