Rebase me: use is_infix directly

Signed-off-by: Benjamin Reis <benjamin.reis@vates.tech>

ocaml/xapi/xapi_vm.ml

@@ -1651,13 +1651,20 @@ let get_secureboot_readiness ~__context ~self =
               Helpers.call_script !Xapi_globs.varstore_ls
                 [Db.VM.get_uuid ~__context ~self]
             in
-            let contains str substr =
-              Astring.String.is_infix ~affix:substr str
+            let ls_lines = String.split_on_char '\n' varstore_ls in
+            let ls_keys =
+              List.map
+                (fun elem ->
+                  (* Lines follow this pattern: <GUID> <KEY>*)
+                  let splitted = String.split_on_char ' ' elem in
+                  List.nth splitted 1
+                )
+                ls_lines
             in
-            let pk_present = contains varstore_ls "PK" in
-            let kek_present = contains varstore_ls "KEK" in
-            let db_present = contains varstore_ls "db" in
-            let dbx_present = contains varstore_ls "dbx" in
+            let pk_present = List.mem "PK" ls_keys in
+            let kek_present = List.mem "KEK" ls_keys in
+            let db_present = List.mem "db" ls_keys in
+            let dbx_present = List.mem "dbx" ls_keys in
             match (pk_present, kek_present, db_present, dbx_present) with
             | true, true, true, true ->
                 `ready