Don't keep user defined role_id and user_id
Don't manipulate the print spec, let's the CGXP Print plugin and the
mapserver_proxy to do what's needed
Patch the print
Sources:
https://github.com/camptocamp/mapfish-print/commits/c2cgeoportal-1.3
Revision:
46700593bcc16163298a00d3625a722799d71196