Previously, the `subprocess` module was used to execute shell command
installing precommit hook. However, after #431 [1], the import of the
`subprocess` module was overriden by `asyncio.subprocess`, which has a
different API to execute the shell command. This change removes the
`asyncio.subprocess` import.
[1] https://github.com/gem5/gem5/pull/431
Change-Id: I9a7d51f85518089d258ab57c5d849a36dcf128e9
Signed-off-by: Hoa Nguyen <hn@hnpl.org>
39fd61d7dd