nixos/redis: remove static uid/gid assignment

all files are chowned on startup

nixos/modules/misc/ids.nix

···
       memcached = 177;
       ntp = 179;
       zabbix = 180;
-      redis = 181;
+      #redis = 181; removed 2018-01-03
       unifi = 183;
       uptimed = 184;
       zope2 = 185;
···
       #memcached = 177; # unused
       #ntp = 179; # unused
       #zabbix = 180; # unused
-      #redis = 181; # unused
+      #redis = 181; # unused, removed 2018-01-03
       #unifi = 183; # unused
       #uptimed = 184; # unused
       #zope2 = 185; # unused

nixos/modules/services/databases/redis.nix

···
 
     users.extraUsers.redis =
       { name = cfg.user;
-        uid = config.ids.uids.redis;
         description = "Redis database user";
       };