raise on focus delay not working

In Xubuntu 19.10, the slider that adjusts the "raise on focus" delay works, but the value seems to be ignored.

Steps:

1. Boot 19.10 Xubuntu live CD to desktop
2. Open Window Manager settings, click Focus tab
3. Set "Focus" to "Focus follows mouse"
4. Check "Automatically raise windows when they receive focus"

Expected results:

Windows should raise after the delay specified by the slider.

Actual results:

Windows raise immediately, regardless of the setting in the slider.

Analysis:

The slider is apparently working since changing it changes the value of `raise_delay` in `~/.config/xfce4/xfconf/xfce-perchannel-xml/xfwm4.xml`.

This was reported upstream by someone else: https://bugzilla.xfce.org/show_bug.cgi?id=15974

The fix is apparently this commit: https://git.xfce.org/xfce/xfwm4/commit?id=daffbf9a321d641803bf710d409f3dcc278d675b

I don't know how the release process for either Xubuntu or XFCE works but it would be nice if this patch could be backported into the eoan updates.