[Bugfix] Fixed the forum bar, change display, buttons  (#3230)
[Bugfix] Fixed the forum bar, change display, buttons  (#3230)

* Fixed the forum bar change display buttons

* check if current thread var exists when rendering forum bar

if the $current thread does not exist it is not being used to render the page anyway so it can safely be set to -1.

This happens when a new thread is being created and therefore that page does not have a current thread id number.

* Removed extra code that was not needed

This code is not needed because
"show_threads" => false,
and therefore the current_thread is not needed to be set

RCOS-Grading-Server/HWserver,RCOS-Grading-Server/HWserver,RCOS-Grading-Server/HWserver,RCOS-Grading-Server/HWserver,Submitty/Submitty,Submitty/Submitty,Submitty/Submitty,RCOS-Grading-Server/HWserver,RCOS-Grading-Server/HWserver,Submitty/Submitty,Submitty/Submitty,Submitty/Submitty,RCOS-Grading-Server/HWserver,RCOS-Grading-Server/HWserver,Submitty/Submitty,Submitty/Submitty,Submitty/Submitty,RCOS-Grading-Server/HWserver