Add lintian override for embedded-zlib

dpkg-deb links statically with zlib so that it can still work
even if the shared library is broken or unavailable. It's a facility
to be able to recover from difficult situations without having
to manually unpack debian packages.

See http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=139320 for
one discussion about this.

debian/dpkg.lintian-overrides

@@ -1,3 +1,5 @@
 dpkg: redundant-origin-field
 dpkg: redundant-bugs-field
 dpkg: arch-dep-package-has-big-usr-share
+# By design, to be able to recover from broken/missing zlib
+dpkg: embedded-zlib ./usr/bin/dpkg-deb