isolated-sstate-dir: resurrect vardeps workaround

JIRA: SB-2551

Signed-off-by: Christopher Larson <kergoth@gmail.com>
Merge pull request #147 from kergoth/sb-2640

Fix git-submodule availability in the buildtools tarball
Merge pull request #139 from kergoth/sb-2551

isolated-sstate-dir: resurrect vardeps workaround
buildtools-tarball: more fallout from including nativesdk-perl

JIRA: SB-2622

Signed-off-by: Christopher Larson <kergoth@gmail.com>