title: Trying to delete Android Realm file, but getting exception
body: <p>I am trying to delete the Realm file to clear cache when a user logs out. </p>
  
  <p>Here is what I'm trying:</p>
  
  <pre><code>Realm realm = Realm.getInstance(activity);
  
  realm.close();
  RealmConfiguration config = realm.getConfiguration();
  
  Realm.deleteRealm(config);
  </code></pre>
  
  <p>I get this exception:</p>
  
  <pre><code>11-05 23:56:00.902 27521-27521/com.my.app E/AndroidRuntime: java.lang.IllegalStateException: It's not allowed to delete the file associated with an open Realm. Remember to close() all the instances of the Realm before deleting its file.
  11-05 23:56:00.902 27521-27521/com.my.app E/AndroidRuntime:     at io.realm.Realm.deleteRealm(Realm.java:1726)
  </code></pre>
  
  <p>I'm obviously closing something, but its saying more are open? How do I close all of the realms so I can blow everything away and start fresh?</p>