fix(remote): assemble exception message completely

Byron · Byron · commit fdc8ecbc0c1d · 2017-02-25T10:16:57.000+01:00
... before trying to substitute values in. Fixes gitpython-developers#575
diff --git a/git/remote.py b/git/remote.py
@@ -706,8 +706,8 @@ def _assert_refspec(self):
             if config.get_value('fetch', default=unset) is unset:
                 msg = "Remote '%s' has no refspec set.\n"
                 msg += "You can set it as follows:"
-                msg += " 'git config --add \"remote.%s.fetch +refs/heads/*:refs/heads/*\"'." % (self.name, self.name)
-                raise AssertionError(msg)
+                msg += " 'git config --add \"remote.%s.fetch +refs/heads/*:refs/heads/*\"'."
+                raise AssertionError(msg % (self.name, self.name))
         finally:
             config.release()
 
