improve osusers admin interface

- set user uid to readonly
- set shadow password readonly
- set can_delete on shadow to False

gnuviechadmin/osusers/admin.py

@@ -14,10 +14,13 @@ class AdditionalGroupInline(admin.TabularInline):
 
 class ShadowInline(admin.TabularInline):
     model = Shadow
+    readonly_fields = ['passwd']
+    can_delete = False
 
 
 class UserAdmin(admin.ModelAdmin):
     inlines = [AdditionalGroupInline, ShadowInline]
+    readonly_fields = ['uid']
 
 
 admin.site.register(Group)