pylint: remove unused imports

Removed unused imports accross multiple files.

Change-Id: Ib5ae4cebf9660e7339b11e3fa592d99f8d51e8d8
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/354700
Tested-by: Daniel Kutik <daniel.kutik@lavawerk.com>
Reviewed-by: Mike Frysinger <vapier@google.com>

run_tests

@@ -15,7 +15,6 @@
 
 """Wrapper to run pytest with the right settings."""
 
-import errno
 import os
 import shutil
 import subprocess