parse: return instead of raising StopIteration.

In Python 3.7 StopIteration is transformed to a RuntimeError.
See PEP 479.

This change is backwards compatible, the exception was
unnecessary in the first place.

closes: Dav1dde#172

glad/parse.py

@@ -496,7 +496,7 @@ def find(self, require, api, profile, recursive=False):
         """
         if not ((require.profile is None or require.profile == profile) and
                 (require.api is None or require.api == api)):
-            raise StopIteration
+            return
 
         if self._combined is None:
             self._combined = dict()