Remove fixed uids for nscd, sshd

These services don't create files on disk, let alone on a network
filesystem, so they don't really need a fixed uid. And this also gets
rid of a warning coming from <= 14.12 systems.

nixos/modules/misc/ids.nix

@@ -203,11 +203,9 @@
       sddm = 175;
       tss = 176;
       memcached = 177;
-      nscd = 178;
       ntp = 179;
       zabbix = 180;
       redis = 181;
-      sshd = 182;
       unifi = 183;
       uptimed = 184;
       zope2 = 185;
@@ -399,11 +397,9 @@
       sddm = 175;
       tss = 176;
       #memcached = 177; # unused
-      #nscd = 178; # unused
       #ntp = 179; # unused
       #zabbix = 180; # unused
       #redis = 181; # unused
-      #sshd = 182; # unused
       #unifi = 183; # unused
       #uptimed = 184; # unused
       #zope2 = 185; # unused