gnome-help.bbclass: remove double FILES_${PN}-help entry
When I wrote this class meta-qt5-extra's qt5-translation.bbclass was taken
as template. So this is a leftover which does not make sense: Variable is set
differently few lines below.
Signed-off-by: Andreas Müller <schnitzeltony@gmail.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>