dpkg: Upgrade to 1.18.7

Rebased patches:

0003-Our-pre-postinsts-expect-D-to-be-set-when-running-in.patch
add_armeb_triplet_entry.patchadd_armeb_triplet_entry.patch

Patches removed already in upstream:

	[1] 0001-When-running-do_package_write_deb-we-have-trees-of-h.patch
	[2] fix-abs-redefine.patch

Signed-off-by: Aníbal Limón <anibal.limon@linux.intel.com>

[1] https://anonscm.debian.org/cgit/dpkg/dpkg.git/commit/dpkg-deb/build.c?id=7a91341446851cd3594a8b752823b8c1f26d652a
[2] https://anonscm.debian.org/cgit/dpkg/dpkg.git/commit/lib/dpkg/i18n.h?id=ecd4baa091619cbbdd70043129dd992573580371


Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>