fix isLocal logic (f*ck yeah unit tests!)

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

@@ -237,6 +237,6 @@ public class WrappedSignature {
             return false;
         }
         SignatureSubpacket p = mSig.getHashedSubPackets().getSubpacket(SignatureSubpacketTags.EXPORTABLE);
-        return ((Exportable) p).isExportable();
+        return ! ((Exportable) p).isExportable();
     }
 }