Don't assume KRB5CCNAME is in the environment in replica install
The replica install was unilaterally removing KRB5CCNAME from
os.environ in some cases. Instead check first to see if it is
present and only remove in that case.
Fixes: https://pagure.io/freeipa/issue/9446
Signed-off-by: Rob Crittenden <rcritten@redhat.com>
Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>