minion: master_alive_interval: remove duplicate (#369)

Remove commented version and associated comment, as we still have the same
option earlier in config with an other valid comment.

salt/files/minion.d/f_defaults.conf

@@ -464,12 +464,6 @@ schedule:
 # minion event bus. The value is expressed in bytes.
 {{ get_config('max_event_size', '1048576') }}
 
-# To detect failed master(s) and fire events on connect/disconnect, set
-# master_alive_interval to the number of seconds to poll the masters for
-# connection events.
-#
-#{{ get_config('master_alive_interval', '30') }}
-
 # The minion can include configuration from other files. To enable this,
 # pass a list of paths to this option. The paths can be either relative or
 # absolute; if relative, they are considered to be relative to the directory