sysui: remove slackware desktop integration stuff

This is apparently not used at all currently; cloph says the
*slackware-menus*.tgz used to be bundled with RPM instsets but the last
release that contained it was apparently OOo 3.1.1; it is gone in OOo
3.2.1 RPM instset.  There are no bug reports about it missing, so no
problem with removing it altogether.

Conflicts:
	sysui/Module_sysui.mk

Change-Id: I1b93c94c4ac5c1d1826069b05cb58fdbb30cd71f