update XDG menu prefix in KDE session script (#1851755)

openbox-kf5menu.patch

@@ -0,0 +1,12 @@
+diff -up openbox-3.6.1/data/xsession/openbox-kde-session.in.kf5menu openbox-3.6.1/data/xsession/openbox-kde-session.in
+--- openbox-3.6.1/data/xsession/openbox-kde-session.in.kf5menu	2011-10-16 18:13:18.000000000 +0200
++++ openbox-3.6.1/data/xsession/openbox-kde-session.in	2020-11-09 10:42:43.755217411 +0100
+@@ -8,7 +8,7 @@ if test -n "$1"; then
+ fi
+ 
+ # Set the prefix for the menu layout to use
+-export XDG_MENU_PREFIX="kde-4-"
++export XDG_MENU_PREFIX="kf5-"
+ 
+ # Clean up after GDM
+ xprop -root -remove _NET_NUMBER_OF_DESKTOPS \

openbox.spec

@@ -11,6 +11,7 @@ Source2:	xdg-menu
 Source3:	menu.xml
 Source4:	terminals.menu
 Patch1:		openbox-python3.patch
+Patch2:		openbox-kf5menu.patch
 
 Requires:	%{name}-libs%{?_isa} = %{version}-%{release}
 
@@ -92,6 +93,7 @@ KDE session.
 %prep
 %setup -q
 %patch1 -p1 -b .python3
+%patch2 -p1 -b .kf5menu
 
 
 %build