[FIX] mail : controller chat_post force text to be plaintext
[FIX] mail : controller chat_post force text to be plaintext

This controller is mainly used by im_livechat which don't send html message. It is more secure to force it in plain text. If anonoymous user write html tags, it will be escaped and sanitize.

laslabs/odoo,dfang/odoo,bplancher/odoo,dfang/odoo,stephen144/odoo,syci/OCB,sysadminmatmoz/OCB,optima-ict/odoo,storm-computers/odoo,stephen144/odoo,dfang/odoo,Elico-Corp/odoo_OCB,storm-computers/odoo,ygol/odoo,stephen144/odoo,syci/OCB,storm-computers/odoo,stephen144/odoo,sysadminmatmoz/OCB,laslabs/odoo,stephen144/odoo,hip-odoo/odoo,bplancher/odoo,sysadminmatmoz/OCB,syci/OCB,optima-ict/odoo,hip-odoo/odoo,laslabs/odoo,Elico-Corp/odoo_OCB,sysadminmatmoz/OCB,laslabs/odoo,bplancher/odoo,sysadminmatmoz/OCB,laslabs/odoo,dfang/odoo,ygol/odoo,microcom/odoo,ygol/odoo,microcom/odoo,ygol/odoo,syci/OCB,storm-computers/odoo,ygol/odoo,optima-ict/odoo,bplancher/odoo,microcom/odoo,microcom/odoo,hip-odoo/odoo,microcom/odoo,microcom/odoo,stephen144/odoo,ygol/odoo,storm-computers/odoo,optima-ict/odoo,hip-odoo/odoo,laslabs/odoo,optima-ict/odoo,Elico-Corp/odoo_OCB,Elico-Corp/odoo_OCB,Elico-Corp/odoo_OCB,syci/OCB,dfang/odoo,bplancher/odoo,sysadminmatmoz/OCB,optima-ict/odoo,sysadminmatmoz/OCB,storm-computers/odoo,dfang/odoo,hip-odoo/odoo,syci/OCB,Elico-Corp/odoo_OCB,bplancher/odoo,ygol/odoo,hip-odoo/odoo