py2: remove simple from __future__ statements
These were needed for Python 2 support. Now that our linter no longer
mandates these, we can start deleting them.
Differential Revision: https://phab.mercurial-scm.org/D12254
import sys
for line in sys.stdin:
if line.lower() in ("message-id: \n", "in-reply-to: \n"):
line = line[:-2]
print(line, end="")