Replace icon to clear HTTP passwords with red cross

Gerrit upstream switched from the Tango to the Silk icon set in

  89773d89f928eff3868e590a6584846877b1e249

. With this change, some icons got removed, like the `deleteHover`
icon we used. Gerrit upstream does not offer an icon that symbolizes
"Clear HTTP password", and it's overkill to add additional icons
within this plugin. Hence we use the redNot icon for the time being
(which is a red cross). Once gerrit upstream provides a better icon,
we should switch to that.

Change-Id: I011431eae8dff099702ebe09e04f88eb488ee6b5
diff --git a/src/main/java/com/googlesource/gerrit/plugins/serviceuser/client/ServiceUserScreen.java b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/client/ServiceUserScreen.java
index 11d39c5..bece2c3 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/serviceuser/client/ServiceUserScreen.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/client/ServiceUserScreen.java
@@ -213,7 +213,9 @@
       label.setVisible(!httpPassword.isEmpty());
       p.add(label);
 
-      final Image delete = new Image(ServiceUserPlugin.RESOURCES.deleteHover());
+      // The redNot icon is only used as temporary measure until gerrit core
+      // provides a better icon that symbolizes "clear".
+      final Image delete = new Image(ServiceUserPlugin.RESOURCES.redNot());
       delete.addStyleName("serviceuser-deleteButton");
       delete.setTitle("Clear HTTP password");
       delete.addClickHandler(new  ClickHandler() {