[FIX] don't cause a warning for the data key (#148)

account_bank_statement_import_camt/models/parser.py

@@ -185,6 +185,8 @@ class CamtParser(models.AbstractModel):
             self.parse_transaction_details(ns, dnode, transaction)
             # transactions['data'] should be a synthetic xml snippet which
             # contains only the TxDtls that's relevant.
+            # only set this field if statement lines have it
+            if 'data' in self.pool['account.bank.statement.line']._fields:
                 data = copy(node)
                 for j, dnode in enumerate(data.xpath(
                         './ns:NtryDtls/ns:TxDtls', namespaces={'ns': ns})):