suppress mutable warnings for primitive arrays (we don't wanna wrap those)

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/ParcelableS2K.java

@@ -44,6 +44,7 @@ public abstract class ParcelableS2K implements Parcelable {
     abstract int getS2kType();
     abstract int getS2kHashAlgo();
     abstract long getS2kItCount();
+    @SuppressWarnings("mutable")
     abstract byte[] getS2kIV();
 
     @Memoized

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpSignEncryptData.java

@@ -40,6 +40,7 @@ public abstract class PgpSignEncryptData implements Parcelable {
     @Nullable
     public abstract Passphrase getSymmetricPassphrase();
     @Nullable
+    @SuppressWarnings("mutable")
     public abstract long[] getEncryptionMasterKeyIds();
     public abstract int getCompressionAlgorithm();
     @Nullable