Removed code which redundantly checks values of sf.spec.splitbuild, sf.spec.os.skipbuild, and sf.spec.s60.skipbuild. Removed setting of sf.spec.sysdef.version, as nothing ever reads its value. Removed sf-check-missing-s60-files, as there's nothing to call it any more.

^SHOWSTOPPER RAISED:	critical
^ERROR:	major
^WARNING: .+ CANNOT BE FOUND IN THE SYSTEM PATH	ignore
^WARNING:	minor