[FIX] maintenance: avoid a crash when the creditential to access the migration server aren't correct
[FIX] maintenance: avoid a crash when the creditential to access the migration server aren't correct

gisce/openobject-server,MarkusTeufelberger/openobject-server,gisce/openobject-server,splbio/openobject-server,vnc-biz/openerp-server,splbio/openobject-server,ovnicraft/openerp-server,splbio/openobject-server,MarkusTeufelberger/openobject-server,vnc-biz/openerp-server,gisce/openobject-server,ovnicraft/openerp-server,xrg/openerp-server,xrg/openerp-server,MarkusTeufelberger/openobject-server