cleanup & fix build

bukkit/src/main/java/me/lucko/luckperms/bukkit/migration/MigrationBPermissions.java

@@ -174,7 +174,7 @@ public class MigrationBPermissions extends SubCommand<Object> {
                 }
 
                 // Make a LuckPerms user for the one being migrated.
-                plugin.getStorage().loadUser(uuid, "null").join();
+                plugin.getStorage().loadUser(uuid, null).join();
                 User lpUser = plugin.getUserManager().getIfLoaded(uuid);
 
                 migrateHolder(world, user, lpUser);

bukkit/src/main/java/me/lucko/luckperms/bukkit/migration/MigrationGroupManager.java

@@ -262,7 +262,7 @@ public class MigrationGroupManager extends SubCommand<Object> {
         log.log("Starting user migration.");
         AtomicInteger userCount = new AtomicInteger(0);
         for (Map.Entry<UUID, Set<Node>> e : users.entrySet()) {
-            plugin.getStorage().loadUser(e.getKey(), "null").join();
+            plugin.getStorage().loadUser(e.getKey(), null).join();
             me.lucko.luckperms.common.model.User user = plugin.getUserManager().getIfLoaded(e.getKey());
 
             for (Node node : e.getValue()) {

bukkit/src/main/java/me/lucko/luckperms/bukkit/migration/MigrationPowerfulPerms.java

@@ -231,7 +231,7 @@ public class MigrationPowerfulPerms extends SubCommand<Object> {
         for (UUID uuid : uuids) {
 
             // Create a LuckPerms user for the UUID
-            plugin.getStorage().loadUser(uuid, "null").join();
+            plugin.getStorage().loadUser(uuid, null).join();
             User user = plugin.getUserManager().getIfLoaded(uuid);
 
             List<Permission> permissions = joinFuture(pm.getPlayerOwnPermissions(uuid));

bukkit/src/main/java/me/lucko/luckperms/bukkit/model/LPPermissible.java

@@ -151,7 +151,7 @@ public class LPPermissible extends PermissibleBase {
      *
      * @return the calculated contexts for the player.
      */
-    public Contexts calculateContexts() {
+    private Contexts calculateContexts() {
         return plugin.getContextManager().getApplicableContexts(player);
     }