tests: make test-manifest use absolute_import

tests/test-check-py3-compat.t

@@ -59,7 +59,6 b''
   tests/test-hgwebdir-paths.py not using absolute_import
   tests/test-lrucachedict.py not using absolute_import
   tests/test-lrucachedict.py requires print_function
-  tests/test-manifest.py not using absolute_import
   tests/test-trusted.py requires print_function
 
 #if py3exe

tests/test-manifest.py

@@ -1,11 +1,14 b''
-import binascii
-import unittest
-import itertools
+from __future__ import absolute_import
 
+import binascii
+import itertools
 import silenttestrunner
+import unittest
 
-from mercurial import manifest as manifestmod
-from mercurial import match as matchmod
+from mercurial import (
+    manifest as manifestmod,
+    match as matchmod,
+)
 
 EMTPY_MANIFEST = ''
 EMTPY_MANIFEST_V2 = '\0\n'