Fix crash when creating github requests

Author: dmerejkowsky

git_repo/services/ext/github.py

@@ -237,7 +237,7 @@ def request_create(self, onto_user, onto_repo, from_branch, onto_branch, title=N
         if not onto_project:
             raise ResourceNotFoundError('Could not find project `{}/{}`!'.format(onto_user, onto_repo))
 
-        from_reposlug = self.guess_repo_slug(self.repository, self)
+        from_reposlug = self.guess_repo_slug(self.repository, self, resolve_targets=['{service}'])
         if from_reposlug:
             from_user, from_repo = from_reposlug.split('/')
             if (onto_user, onto_repo) == (from_user, from_repo):