[freeipa PR#1134][opened] [Backport][ipa-4-6] Remove the `message` attribute from exceptions

[stlaz]

   URL: https://github.com/freeipa/freeipa/pull/1134
Author: stlaz
 Title: #1134: [Backport][ipa-4-6] Remove the `message` attribute from exceptions
Action: opened

PR body:
"""
This PR was opened automatically because PR #1121 was pushed to master and backport to
ipa-4-6 is required.
"""

To pull the PR as Git branch:
git remote add ghfreeipa https://github.com/freeipa/freeipa
git fetch ghfreeipa pull/1134/head:pr1134
git checkout pr1134