Remove non-working css for OK button

This was an attempt to horizontally center the OK button but it is not
working.

Change-Id: I61467989c5c7d669fa197af4b4bb67cc157bd418
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>
diff --git a/src/main/java/com/googlesource/gerrit/plugins/serviceuser/client/CreateServiceUserForm.java b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/client/CreateServiceUserForm.java
index dbcf5a4..2dfbe18 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/serviceuser/client/CreateServiceUserForm.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/client/CreateServiceUserForm.java
@@ -180,7 +180,6 @@
         p.setStyleName("panel");
         p.add(new Label("The service user '" + username + "' was created."));
         Button okButton = new Button("OK");
-        okButton.addStyleName("okButton");
         okButton.addClickHandler(new ClickHandler() {
           public void onClick(ClickEvent event) {
             successDialog.hide();
diff --git a/src/main/java/com/googlesource/gerrit/plugins/serviceuser/public/serviceuser.css b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/public/serviceuser.css
index 2f66127..1b8d364 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/serviceuser/public/serviceuser.css
+++ b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/public/serviceuser.css
@@ -106,8 +106,3 @@
   margin-right: 450px !important;
 }
 
-.okButton {
-  margin-left: auto;
-  margin-right: auto;
-}
-