DISTRO_CODENAME is part of VERSION variable but not used as dependency
for do_compile task. Append it to the vardeps list to rebuild in case it
changes.
(From OE-Core rev: ee0345057459c6d77fb64902a955e836c6c1e8e4)
Signed-off-by: Daniel Gomez <daniel@qtec.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>