BUG: dirac-admin-add-user

[graciani]

if the permission are not OK the script launches an exception, instead of printing a proper error:

$ dirac-admin-add-user -N atsareg -D "/O=GRID-FR/C=FR/O=CNRS/OU=CPPM/CN=Andrei Tsaregorodtsev" -M "atsareg@in2p3.fr" -G user
No proxy found 
No proxy found! 
  File "/opt/dirac/versions/v6r3p6_1334935615/DIRAC/Interfaces/scripts/dirac-admin-add-user.py", line 84, in <module>
    if not diracAdmin.csModifyUser( userName, userProps, createIfNonExistant = True )['Value']:
KeyError: 'Value'

[atsareg]

Fixed in #691