Remove line with whitespaces in fs.base failing flake8 linter

Author: althonos

fs/base.py

@@ -1308,7 +1308,7 @@ def upload(self, path, file, chunk_size=None, **options):
                 sensible default.
             **options: Implementation specific options required to open
                 the source file.
-                
+
         Raises:
             fs.errors.ResourceNotFound: If a parent directory of
                 ``path`` does not exist.