krebs: use prism binary cache on all hosts

krebs/1systems/puyak/config.nix

@@ -9,6 +9,7 @@
 
     <stockholm/krebs/2configs/buildbot-krebs.nix>
     <stockholm/krebs/2configs/stats/puyak-client.nix>
+    <stockholm/krebs/2configs/binary-cache/prism.nix>
   ];
 
   krebs.build.host = config.krebs.hosts.puyak;

krebs/1systems/wolf/config.nix

@@ -13,6 +13,7 @@ in
 
     <stockholm/krebs/2configs/graphite.nix>
     <stockholm/krebs/2configs/buildbot-krebs.nix>
+    <stockholm/krebs/2configs/binary-cache/prism.nix>
 
     <stockholm/krebs/2configs/shack/worlddomination.nix>
     <stockholm/krebs/2configs/shack/drivedroid.nix>
@@ -44,11 +45,9 @@ in
   nix = {
     # use the up to date prism cache
     binaryCaches = [
-      "http://cache.prism.r"
       "https://cache.nixos.org/"
     ];
     binaryCachePublicKeys = [
-      "cache.prism-1:+S+6Lo/n27XEtvdlQKuJIcb1yO5NUqUCE2lolmTgNJU="
       "hydra.nixos.org-1:CNHJZBh9K4tP3EKF6FkkgeVYsS3ohTl+oS0Qa8bezVs="
     ];
   };

krebs/2configs/binary-cache/prism.nix

@@ -0,0 +1,12 @@
+{ config, ... }:
+
+{
+  nix = {
+    binaryCaches = [
+      "http://cache.prism.r"
+    ];
+    binaryCachePublicKeys = [
+      "cache.prism-1:+S+6Lo/n27XEtvdlQKuJIcb1yO5NUqUCE2lolmTgNJU="
+    ];
+  };
+}