Fix upload the file into blob field by using class Form (#1043)

* fixed upload file into blob with class Form

* fixed upload file into blob with class Form

* allows delete of blob

Author: ls1luke

py4web/utils/form.py

@@ -924,6 +924,10 @@ def process(self):
                             validated_vars[field.name] = self.record.get(field.name)
                         else:
                             validated_vars[field.name] = value = None
+                    if isinstance(field.uploadfield, str) and value is not None:
+                        validated_vars[field.uploadfield] = value.file.read()
+                elif field.type == 'blob':
+                    pass
                 elif field.type == "boolean":
                     validated_vars[field.name] = value is not None
                 else: