ipatests: Replace 'usermod -r' command with 'gpasswd -d' in test_hsm.py
Test 'test_hsm_negative_bad_token_dir_permissions'
was failing in RHEL because of the below error.
"ipa: ERROR: stderr: usermod: invalid option -- 'r'"
Hence replaced the usermod with gpasswd command which does the same and
works on both RHEL and Fedora.
Ref: https://pagure.io/freeipa/issue/9626
Signed-off-by: Sudhir Menon <sumenon@redhat.com>
Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>