Move change note to new location and remove import

Co-authored-by: Anders Schack-Mulligen <aschackmull@users.noreply.github.com>

Author: atorralba

java/ql/lib/semmle/code/java/security/CleartextStorageSharedPrefsQuery.qll

@@ -2,7 +2,6 @@
 
 import java
 import semmle.code.java.dataflow.DataFlow
-import semmle.code.java.dataflow.DataFlow4
 import semmle.code.java.frameworks.android.SharedPreferences
 import semmle.code.java.security.CleartextStorageQuery