xfce4-settings: Install cursors from srcdir

Cursors patched into the install by 0001-add-cursor-theme-xfce-invisible.patch
are located in the source directory.  To install during an out-of-tree build,
we need to copy them from the source directory, not the current build
directory. See [1] for discussion.

Upstream-Status: Submitted

[1] https://bugzilla.xfce.org/show_bug.cgi?id=9474



Signed-off-by: Ash Charles <ashcharles@gmail.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>