[GOBBLIN-2109] Fix minor permission issues with setPermissionCommitStep in Manifest distcp

[Will-Lo]

Dear Gobblin maintainers,

Please accept this PR. I understand that it will not be reviewed until I have checked off all the steps below!

JIRA

• My PR addresses the following Gobblin JIRA issues and references them in the PR title. For example, "[GOBBLIN-XXX] My Gobblin PR"
  • https://issues.apache.org/jira/browse/GOBBLIN-2109

Description

• Here are some details about my PR, including screenshots (if applicable):
  This PR adds some minor fixes to ensure that permissions setting in Manifest distcp correctly resets folder permissions after adding execute bit along with tests, and ensures that the ownerAndPermission list is reset in between the writers and the commit step by using list iterator

Tests

• My PR adds the following unit tests OR does not need testing for this extremely good reason:
  Unit tests

Commits

• My commits all reference JIRA issues in their subject lines, and I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"