remove unnecessary files

Signed-off-by: alex <alex.plutta@googlemail.com>
Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

src/main/java/com/owncloud/android/ui/activities/ActivityListElement.java

@@ -1,4 +0,0 @@
-package com.owncloud.android.ui.activities;
-
-public interface ActivityListElement {
-}

src/main/java/com/owncloud/android/ui/activities/ActivityListHeader.java

@@ -1,14 +0,0 @@
-package com.owncloud.android.ui.activities;
-
-public class ActivityListHeader implements ActivityListElement {
-    final private String headline;
-
-    public ActivityListHeader(String headline) {
-        this.headline = headline;
-    }
-
-    public String getHeadline() {
-        return headline;
-    }
-
-}