[IMP] website_slides: do not crash when installing the module offline.
[IMP] website_slides: do not crash when installing the module offline.

Catch URLError when trying to fetch videos / google doc data.

laslabs/odoo,ygol/odoo,cdrooom/odoo,mkieszek/odoo,odoousers2014/odoo,addition-it-solutions/project-all,hip-odoo/odoo,bplancher/odoo,ygol/odoo,ygol/odoo,Elico-Corp/odoo_OCB,ygol/odoo,addition-it-solutions/project-all,mkieszek/odoo,syci/OCB,mkieszek/odoo,syci/OCB,cdrooom/odoo,ygol/odoo,odoousers2014/odoo,stephen144/odoo,optima-ict/odoo,sysadminmatmoz/OCB,storm-computers/odoo,ygol/odoo,hip-odoo/odoo,optima-ict/odoo,dfang/odoo,dfang/odoo,stephen144/odoo,deKupini/erp,Grirrane/odoo,alhashash/odoo,sysadminmatmoz/OCB,microcom/odoo,optima-ict/odoo,deKupini/erp,storm-computers/odoo,alhashash/odoo,sysadminmatmoz/OCB,laslabs/odoo,optima-ict/odoo,bplancher/odoo,tvtsoft/odoo8,laslabs/odoo,bplancher/odoo,hip-odoo/odoo,Grirrane/odoo,odoousers2014/odoo,sysadminmatmoz/OCB,laslabs/odoo,addition-it-solutions/project-all,mkieszek/odoo,tvtsoft/odoo8,microcom/odoo,cdrooom/odoo,Grirrane/odoo,tvtsoft/odoo8,odoousers2014/odoo,dfang/odoo,tvtsoft/odoo8,deKupini/erp,microcom/odoo,optima-ict/odoo,alhashash/odoo,laslabs/odoo,dfang/odoo,Grirrane/odoo,syci/OCB,stephen144/odoo,optima-ict/odoo,odoousers2014/odoo,sysadminmatmoz/OCB,storm-computers/odoo,storm-computers/odoo,Grirrane/odoo,syci/OCB,bplancher/odoo,tvtsoft/odoo8,alhashash/odoo,bplancher/odoo,addition-it-solutions/project-all,alhashash/odoo,microcom/odoo,Elico-Corp/odoo_OCB,sysadminmatmoz/OCB,syci/OCB,deKupini/erp,dfang/odoo,addition-it-solutions/project-all,bplancher/odoo,alhashash/odoo,tvtsoft/odoo8,Elico-Corp/odoo_OCB,storm-computers/odoo,microcom/odoo,deKupini/erp,mkieszek/odoo,sysadminmatmoz/OCB,hip-odoo/odoo,ygol/odoo,storm-computers/odoo,cdrooom/odoo,mkieszek/odoo,hip-odoo/odoo,Elico-Corp/odoo_OCB,dfang/odoo,odoousers2014/odoo,Grirrane/odoo,Elico-Corp/odoo_OCB,laslabs/odoo,stephen144/odoo,stephen144/odoo,addition-it-solutions/project-all,microcom/odoo,hip-odoo/odoo,syci/OCB,stephen144/odoo,Elico-Corp/odoo_OCB