Fix regex match group handling after moving to case statements

The rubocop autocorrect for Style/CaseLikeIf does not take into
account the match operator for regex, which in this case
returns the matched data when using it with and if/elsif statement.
After just moving this to an case statement, the data is not returned
anymore.
This could be fixed by using the `$LAST_MATCH_INFO` pseudo variable which
contains the whole `MatchData` object of the latest regex matching group.

src/api/app/controllers/webui/repositories_controller.rb

@@ -197,9 +197,9 @@ def follow_change_flag_command(flag_type)
     case params[:command]
     when 'remove'
       @main_object.flags.of_type(flag_type).where(repo: params[:repository], architecture: architecture).delete_all
-    when %r{^set-(?<status>disable|enable)$}
+    when /^set-(?<status>disable|enable)$/
       flag = @main_object.flags.find_or_create_by(flag: flag_type, repo: params[:repository], architecture: architecture)
-      flag.update(status: status)
+      flag.update(status: $LAST_MATCH_INFO['status'])
     end
     @main_object.store
   end