do not try to parse lines which do not conform to the browserpass format

bwpass.py

@@ -53,6 +53,9 @@ def _get_contents_from_pass(identifier: str):
 
         if len(pass_output) > 1:
             for line in pass_output[1:]:
+                if not ':' in line:
+                    continue
+
                 attr, value = line.split(':', 1)
 
                 cache[identifier]['attrs'][attr] = value.strip()