Fixed issue #2327: Help button is broken in "SVN Commit Type" dialog

Signed-off-by: Sven Strickroth <email@cs-ware.de>
Drop unused variable

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Check file size before checking content

Signed-off-by: Sven Strickroth <email@cs-ware.de>