libacl: Remove unnecessary assignment

Don't assign i to j, when we never use j again in the function

Caught by clang-analyzer

Change-Id: I9dd2d929019ac3cc84cde4e44c4883806bd5964a
Reviewed-on: http://gerrit.openafs.org/9175
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>