Fix issue with terror closest failing.

galaxy.py

@@ -480,6 +480,9 @@ class GameData(object):
                         continue
                     sc = sp["class"]
 
+                    if s not in self.warps:
+                        continue
+
                     log.warn("{0} has warps {1}".format(s, self.warps[s]))
 
                     # Ok, check for tradepairs.