Fix bug [YOCTO #1092]
Own a directory "/var/lib" before do_install() because if there isn't this directory during installing, \
then script "mkinstalldirs" from "sudo package" will create directory "/var/lib/sudo" by recursion with mode "0700" \
which will cause bug [YOCTO #1092]. So I add do_install_prepend() to create a "/var/lib" which can be accessed \
by common user before installing files.
Signed-off-by: Xiaofeng Yan <xiaofeng.yan@windriver.com>
