Python: Fix minor bug in modernisation-rewrite

Obviously the result module shouldn't be a package 🤦 I was confusing
myself, since I wanted to say that `Module::named("Crypto.Cipher")` should be a package :D

python/ql/src/semmle/python/security/Crypto.qll

@@ -16,8 +16,7 @@ abstract class WeakCryptoSink extends TaintSink {
 module Pycrypto {
 
     ModuleValue cipher(string name) {
-        result = Module::named("Crypto.Cipher").attr(name) and
-        result.isPackage()
+        result = Module::named("Crypto.Cipher").attr(name)
     }
 
     class CipherInstance extends TaintKind {