extract: indent code, no semantics change

prepare for a extract_helper context manager

(some changes may seem superfluous, but see the following changesets)

src/borg/archive.py

@@ -579,6 +579,7 @@ def make_parent(path):
                 elif chunks is not None:
                     # assign chunks to this item, since the item which had the chunks was not extracted
                     item.chunks = chunks
+            if True:
                 if hardlink_set:
                     return
                 if sparse and self.zeros is None: