Remove build_config.rb from debian directory

This fuction was moved to patch.

Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Add dep3 header

Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Change distribution to unstable

Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>