fix: chattr exits with status 1 for files that are not permitted without force flag

[Glitchfix]

What this PR does / why we need it:
chattr exits with status 1 for files that are not permitted without force flag

Which issue(s) this PR fixes (optional)
PWX-32298
It was obsereved that the package was throwing error despite of setting the immutability flags properly.

 Operation not supported while reading flags on /var/lib/kubelet/plugins_registry/pxd.portworx.com-reg.sock

Testing Notes
Use the package to set immutability flags on node registration socket,
use the ForceAddImmutable method to set the immutability flags
it can be compared to AddImmutable that ForceAddImmutable does set the flags successfully

[ggriffiths]

Let's try to avoid changing the functionality of code when not needed. This chattr package is called on every Mount/Unmount for every volume. So, changing the contract of how we return errors can lead to bugs.

[ggriffiths]

@Glitchfix can you fix the travis failure?

git-validation -run DCO,short-subject
 * 9a01976 "refactor: [minor refactor] remove extra line and return nil to not break existing mount functionalities" ... FAIL
  - FAIL - commit subject exceeds 90 characters

[github-actions]

This PR is stale because it has been in review for 3 days with no activity.