remove unused import

Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

src/main/java/com/owncloud/android/ui/fragment/contactsbackup/ContactsBackupFragment.java

@@ -28,7 +28,6 @@ import android.content.DialogInterface;
 import android.content.Intent;
 import android.os.AsyncTask;
 import android.os.Bundle;
-import android.os.storage.StorageManager;
 import android.view.LayoutInflater;
 import android.view.MenuItem;
 import android.view.View;