fix: correct case when application has no ResPackages

- refs: #2701

brut.apktool/apktool-lib/src/main/java/brut/androlib/res/AndrolibResources.java

@@ -65,6 +65,9 @@ final public class AndrolibResources {
         ResPackage pkg;
 
         switch (pkgs.length) {
+            case 0:
+                pkg = null;
+                break;
             case 1:
                 pkg = pkgs[0];
                 break;