sysvinit-inittab: Use UNPACKDIR instead of WORKDIR

Now that UNPACKDIR has been introduced to OE-Core, use it in the
do_install fuction so that as/when things move around and UNPACKDIR
is no longer WORKDIR, it continues to work correctly.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

recipes-core/sysvinit/sysvinit-inittab_virtualization.inc

@@ -4,6 +4,6 @@ SRC_URI += "file://getty-wrapper"
 
 do_install:append() {
     install -d ${D}${base_sbindir}
-    install -m 0755 ${WORKDIR}/getty-wrapper ${D}${base_sbindir}/getty-wrapper
+    install -m 0755 ${UNPACKDIR}/getty-wrapper ${D}${base_sbindir}/getty-wrapper
 }
 FILES:${PN} += "${base_sbindir}/getty-wrapper"