test-fastannotate: close fd before unlinking to keep Windows happy

tests/test-fastannotate-revmap.py

@@ -11,8 +11,8 b' def genhsh(i):'
 
 def gettemppath():
     fd, path = tempfile.mkstemp()
+    os.close(fd)
     os.unlink(path)
-    os.close(fd)
     return path
 
 def ensure(condition):