When a shallow mirror tarball is used to satisfy a gitsm URI it needs to
be unpacked temporarily so that the .gitmodules file can be examined.
(Bitbake rev: 3987db953e414255ce278bc25a5f6cec0f2a30c7)
Signed-off-by: Paul Barker <pbarker@konsulko.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>