fixed exception in case of file not found

Author: glpatcern

cs3client/file.py

@@ -226,6 +226,7 @@ def write_file(
             else:
                 headers = {
                     "Upload-Length": str(size),
+                    "Content-Length": str(size),
                     "X-Reva-Transfer": protocol.token,
                     **dict([auth_token]),
                     "X-Lock-Id": lock_id,
@@ -318,7 +319,10 @@ def read_file(self, auth_token: tuple, resource: Resource, lock_id: Optional[str
                 f'msg="Error downloading file from Reva" code="{fileget.status_code}" '
                 f'reason="{status_msg}"'
             )
-            raise IOError(fileget.reason)
+            if fileget.status_code == http.client.NOTFOUND:
+                raise NotFoundException()
+            else:
+                raise IOError(fileget.reason)
         else:
             self._log.info(
                 f'msg="File open for read" {resource.get_file_ref_str()} elapsedTimems="{(tend - tstart) * 1000:.1f}"'