insane: Fix populate_sysroot sanity test path

This was correct for native/cross paths but not for target ones which
meant the tests weren't running in some cases. Fix the path to be
correct in both cases.

(From OE-Core rev: 3739aaf644d5a0f28e85fd07c67cecbfa5b8fb8a)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/insane.bbclass

@@ -1130,7 +1130,7 @@ addtask do_package_qa_setscene
 python do_qa_staging() {
     bb.note("QA checking staging")
 
-    if not package_qa_check_staged(d.expand('${SYSROOT_DESTDIR}${STAGING_LIBDIR}'), d):
+    if not package_qa_check_staged(d.expand('${SYSROOT_DESTDIR}${libdir}'), d):
         bb.fatal("QA staging was broken by the package built above")
 }