[FIX] tools: lxml.etree.XMLSyntaxError if html is empty
[FIX] tools: lxml.etree.XMLSyntaxError if html is empty

Don't try to parse html as xml if html is empty

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