nix: clean up various things for upcoming GC

Signed-off-by: Raito Bezarius <masterancpp@gmail.com>

modules/android-cache.nix

@@ -1,7 +1,7 @@
 { lib, ... }:
 let
   mirrors = {
-    "https://android.googlesource.com" = "/var/lib/src/aosp/mirror";
+    # "https://android.googlesource.com" = "/mnt/aospaosp/mirror";
     "https://github.com/LineageOS" = "/var/lib/src/lineageos/LineageOS";
     "https://github.com/TheMuppets" = "/var/lib/src/themuppets/TheMuppets";
   };

modules/hydra/coordinator.nix

@@ -1,6 +1,6 @@
 { pkgs, ... }: {
   services.hydra = {
-    enable = true;
+    enable = false;
     hydraURL = "https://hydra.newtype.fr";
     notificationSender = "hydra@localhost";
     buildMachinesFiles = [ "/etc/nix/machines" ];

modules/nix-daemon.nix

@@ -57,8 +57,8 @@ in
       nrBuildUsers = 128;
 
       settings = {
-        keep-outputs = true;
-        keep-derivations = true;
+        keep-outputs = false;
+        keep-derivations = false;
         use-cgroups = true;
         http-connections = 0;
         auto-allocate-uids = true;
@@ -76,7 +76,7 @@ in
         ];
         experimental-features = [
           "auto-allocate-uids"
-          "ca-derivations"
+          # "ca-derivations" this feature is really extremely broken.
           "cgroups"
           "discard-references"
           "fetch-closure"