Rename 'plugin.css' to 'serviceuser.css'

The '.css' files of GWT plugins must have unique names. Rename the
'plugin.css' to avoid clashes with other plugins.

Change-Id: I7d9c5e258d0d47933c3028b81e0b71ae44ea90bb
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>
diff --git a/src/main/java/com/googlesource/gerrit/plugins/serviceuser/CreateServiceUserForm.gwt.xml b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/CreateServiceUserForm.gwt.xml
index 4d6c6c8..25ad4e0 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/serviceuser/CreateServiceUserForm.gwt.xml
+++ b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/CreateServiceUserForm.gwt.xml
@@ -26,5 +26,5 @@
   <!-- added in order to make this plugin as simple as possible   -->
   <!-- Specify the app entry point class.                         -->
   <entry-point class="com.googlesource.gerrit.plugins.serviceuser.client.CreateServiceUserForm"/>
-  <stylesheet src="plugin.css"/>
+  <stylesheet src="serviceuser.css"/>
 </module>
diff --git a/src/main/java/com/googlesource/gerrit/plugins/serviceuser/public/plugin.css b/src/main/java/com/googlesource/gerrit/plugins/serviceuser/public/serviceuser.css
similarity index 100%
rename from src/main/java/com/googlesource/gerrit/plugins/serviceuser/public/plugin.css
rename to src/main/java/com/googlesource/gerrit/plugins/serviceuser/public/serviceuser.css