Select query for test Execution occur 500 error

[archonwang]

@marius-balteanu , please help to check it.

when I add a query to test Execution on the execution & result TAB, it occurred 500 error. Thanks.

my environment is

Environment:
  Redmine version                3.3.4.stable.16963
  Ruby version                   2.2.4-p230 (2015-12-16) [x86_64-linux]
  Rails version                  4.2.7.1
  Environment                    production
  Database adapter               Mysql2

Started GET "/projects/demo/redcaser/querytestcases/94?execution_suite_id=" for 10.1.200.167 at 2017-09-16 17:43:54 +0800
Processing by Redcaser::QuerytestcasesController#show as */*
  Parameters: {"execution_suite_id"=>"", "project_id"=>"demo", "id"=>"94"}
  Current user: hui.wang (id=8)
Completed 500 Internal Server Error in 15ms (ActiveRecord: 3.5ms)
  Rendered /usr/local/rvm/gems/ruby-2.2.4@newgemset/gems/exception_notification-4.2.1/lib/exception_notifier/views/exception_notifier/_request.text.erb (0.7ms)
  Rendered /usr/local/rvm/gems/ruby-2.2.4@newgemset/gems/exception_notification-4.2.1/lib/exception_notifier/views/exception_notifier/_title.text.erb (0.6ms)
  Rendered /usr/local/rvm/gems/ruby-2.2.4@newgemset/gems/exception_notification-4.2.1/lib/exception_notifier/views/exception_notifier/_session.text.erb (1.3ms)
  Rendered /usr/local/rvm/gems/ruby-2.2.4@newgemset/gems/exception_notification-4.2.1/lib/exception_notifier/views/exception_notifier/_title.text.erb (0.4ms)
  Rendered /usr/local/rvm/gems/ruby-2.2.4@newgemset/gems/exception_notification-4.2.1/lib/exception_notifier/views/exception_notifier/_environment.text.erb (2.5ms)
  Rendered /usr/local/rvm/gems/ruby-2.2.4@newgemset/gems/exception_notification-4.2.1/lib/exception_notifier/views/exception_notifier/_title.text.erb (0.4ms)
  Rendered /usr/local/rvm/gems/ruby-2.2.4@newgemset/gems/exception_notification-4.2.1/lib/exception_notifier/views/exception_notifier/_backtrace.text.erb (0.4ms)
  Rendered /usr/local/rvm/gems/ruby-2.2.4@newgemset/gems/exception_notification-4.2.1/lib/exception_notifier/views/exception_notifier/_title.text.erb (0.4ms)
  Rendered /usr/local/rvm/gems/ruby-2.2.4@newgemset/gems/exception_notification-4.2.1/lib/exception_notifier/views/exception_notifier/exception_notification.text.erb (14.7ms)

NoMethodError (undefined method `count' for nil:NilClass):
  plugins/redmine_issues_tree_view/lib/issue_query_patch.rb:15:in `issues'
  plugins/redmine_redcaser/app/controllers/redcaser/querytestcases_controller.rb:7:in `show'
  lib/redmine/sudo_mode.rb:63:in `sudo_mode'