[FIX] pos_mercury: escape_html does not exist

It's called html_escape. Introduced in
e2f1af78.

opw-779720

addons/pos_mercury/models/pos_mercury_transaction.py

@@ -52,7 +52,7 @@ class MercuryTransaction(models.Model):
 
         soap_header = '<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:mer="http://www.mercurypay.com"><soapenv:Header/><soapenv:Body><mer:CreditTransaction><mer:tran>'
         soap_footer = '</mer:tran><mer:pw>' + data['merchant_pwd'] + '</mer:pw></mer:CreditTransaction></soapenv:Body></soapenv:Envelope>'
-        xml_transaction = soap_header + misc.escape_html(xml_transaction) + soap_footer
+        xml_transaction = soap_header + misc.html_escape(xml_transaction) + soap_footer
 
         response = ''