Add refresh icon to v21 theme

src/main/java/eu/siacs/conversations/ui/EditAccountActivity.java

@@ -1,6 +1,5 @@
 package eu.siacs.conversations.ui;
 
-import android.app.AlertDialog;
 import android.app.AlertDialog.Builder;
 import android.app.PendingIntent;
 import android.content.DialogInterface;

src/main/res/values-v21/themes.xml

@@ -21,6 +21,7 @@
         <item name="attr/icon_done">@drawable/ic_done_black_24dp</item>
         <item name="attr/icon_group">@drawable/ic_group_white_24dp</item>
         <item name="attr/icon_new">@drawable/ic_add_white_24dp</item>
+        <item name="attr/icon_refresh">@drawable/ic_refresh_grey600_24dp</item>
         <item name="attr/icon_new_attachment">@drawable/ic_attach_file_white_24dp</item>
         <item name="attr/icon_not_secure">@drawable/ic_lock_open_white_24dp</item>
         <item name="attr/icon_remove">@drawable/ic_delete_grey600_24dp</item>