resets file pointer to 0

ckanext/odsh/lib/uploader.py

@@ -29,6 +29,7 @@ def _raise_validation_error_if_virus_found(filename, upload_file):
 
 
 def calculate_hash(upload_file):
+    upload_file.seek(0)
     hash_md5 = hashlib.md5()
     for chunk in iter(lambda: upload_file.read(4096), b""):
             hash_md5.update(chunk)