[FIX] web_calendar: do not use magic var `event`.
[FIX] web_calendar: do not use magic var `event`.

It works in Chrome, but not in Firefox.

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