fix(check-deployment): fix nvd invocation and diff flag

scripts/check-deployment.sh

@@ -13,7 +13,7 @@ By default check all nodes
 
 where:
     -h        Show this help text
-    --dryrun  Print the nixos-anywhere invocation
+    --diff    Show diff with nvd
 
 Exemple:
     check-deployment web01"
@@ -96,9 +96,9 @@ while IFS=$'\n' read -r c; do
 
   if [ "$expected_path" == "$current_path" ] ; then
     echo "$machine -> OK"
-  elif [[ -z ${diff-} ]] ; then
-    nix-store -r "$drv_path"
+  elif [[ -n ${diff-} ]] ; then
     nix-copy-closure --from "root@$domain" "$current_path"
+    nix-store -r "$drv_path"
     echo "$machine -> error. nvd output:"
     @nvd@/bin/nvd  diff "$expected_path" "$current_path"
     return_status=1

scripts/default.nix

@@ -6,6 +6,7 @@ let
       bash
       colmena
       coreutils
+      nvd
       git
       jq;
   };