Borgbackup: Accept unknown hosts

Fixes #118

morph/lib/borgbackup.nix

@@ -53,7 +53,7 @@ in {
           passCommand = "cat /run/keys/borgbackup/passphrase";
         };
         environment = {
-          BORG_RSH = "ssh -i /run/keys/borgbackup/ssh-key";
+          BORG_RSH = "ssh -i /run/keys/borgbackup/ssh-key -o StrictHostKeyChecking=accept-new";
         };
 
         # Ciphertext doesn't compress well
@@ -72,7 +72,7 @@ in {
       path = [ pkgs.borgbackup ];
       environment = {
         BORG_PASSCOMMAND = "cat /run/keys/borgbackup/passphrase";
-        BORG_RSH = "ssh -i /run/keys/borgbackup/ssh-key";
+        BORG_RSH = "ssh -i /run/keys/borgbackup/ssh-key -o StrictHostKeyChecking=accept-new";
         BORG_REPO = lib.fileContents "${publicKeyPath}/borgbackup/${config.networking.hostName}.repopath";
       };
       script = ''${pkgs.borgbackup}/bin/borg check'';