procutil: avoid an uninitialized variable usage on tempfile exception
If `pycompat.unnamedtempfile()` raises an exception, it would have called
`stdin.close()` in the `finally` block without it being initialized first.
Differential Revision: https://phab.mercurial-scm.org/D11928
from __future__ import absolute_import
import hashlib
try:
from ..thirdparty import sha1dc # pytype: disable=import-error
sha1 = sha1dc.sha1
except (ImportError, AttributeError):
sha1 = hashlib.sha1