Fixed cache_max_age default value

kayleevc/plugins/darksky.py

@@ -45,7 +45,7 @@ class Plugin(PluginBase):
         )
         try:
             self._cache_max_age = self.options['cache_max_age']
-        except NameError:
+        except KeyError:
             self._cache_max_age = 1800
 
         self.commands = {