keyring: fix bad dep ordering that prevented ~/private from being mounted

hosts/common/home/keyring.nix

@@ -7,5 +7,6 @@
     generated.script.script = builtins.readFile ../../../scripts/init-keyring;
     # TODO: is this `wantedBy` needed? can we inherit it?
     wantedBy = [ config.sane.fs."/home/colin/private".unit ];
+    wantedBeforeBy = [ ];  # don't created this as part of `multi-user.target`
   };
 }