Expression is always present in rules #74

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

src/licensedcode/models.py

@@ -655,10 +655,6 @@ def __attrs_post_init__(self, *args, **kwargs):
                 raise Exception(message)
 
         # build expression from available data if not present
-        if not self.license_expression:
-            kw = self.license_choice and ' OR ' or ' AND '
-            self.license_expression = kw.join(self.licenses).strip()
-
         if self.license_expression:
             try:
                 expression = self.licensing.parse(self.license_expression)