Fix some warnings

IntelliJ was complaining:
- Delete unused constant;
- Fix what looks a lot like an fd leak.

Test: atest MicrodroidTests
Change-Id: I9760fe4a92986794a28b587936f4b242d1a4df6b
diff --git a/javalib/src/android/system/virtualmachine/VirtualMachine.java b/javalib/src/android/system/virtualmachine/VirtualMachine.java
index ba7174e..902ed72 100644
--- a/javalib/src/android/system/virtualmachine/VirtualMachine.java
+++ b/javalib/src/android/system/virtualmachine/VirtualMachine.java
@@ -1227,8 +1227,7 @@
         if (configPath == null) {
             return Collections.emptyList();
         }
-        try {
-            ZipFile zipFile = new ZipFile(context.getPackageCodePath());
+        try (ZipFile zipFile = new ZipFile(context.getPackageCodePath())) {
             InputStream inputStream =
                     zipFile.getInputStream(zipFile.getEntry(configPath));
             List<String> apkList =
diff --git a/javalib/src/android/system/virtualmachine/VirtualMachineConfig.java b/javalib/src/android/system/virtualmachine/VirtualMachineConfig.java
index 5842d01..c364b42 100644
--- a/javalib/src/android/system/virtualmachine/VirtualMachineConfig.java
+++ b/javalib/src/android/system/virtualmachine/VirtualMachineConfig.java
@@ -69,7 +69,6 @@
     private static final String KEY_DEBUGLEVEL = "debugLevel";
     private static final String KEY_PROTECTED_VM = "protectedVm";
     private static final String KEY_MEMORY_BYTES = "memoryBytes";
-    private static final String KEY_NUM_CPUS = "numCpus";
     private static final String KEY_CPU_TOPOLOGY = "cpuTopology";
     private static final String KEY_ENCRYPTED_STORAGE_BYTES = "encryptedStorageBytes";
     private static final String KEY_VM_OUTPUT_CAPTURED = "vmOutputCaptured";