opkg: Fix possible installation of GPLv3 header

opkg is GPLv2+ licensed but it has optional support for sha256 checksums which
was GPLv3+ licensed. This code is not built unless '--enable-sha256' is passed
to the configure script, the default is equivalent to '--disable-sha256'.

However, the header 'sha256.h', which is GPLv3+ licensed, is in the list of
header files to be installed and thus could end up in the libopkg-dev package.
As this header is installed to '/usr/include/libopkg' it is very unlikely that
it will ever be used. However, if you're uncomfortable with GPLv3 code going
anywhere near your target filesystem you won't want this to happen.

The simplest solution is to replace the sha256 implementation in opkg with the
implementation from coreutils-6.9 which is licensed under GPLv2+. This is
committed to the opkg subversion repository as r652/r653.

The only intervening commit between r650 (previous SRCREV) and this is r651,
which integrates 'obsolete_automake_macros.patch' into the opkg sources. Thus
this patch isn't needed in oe-core anymore.

(Note: Before 873689bbabba25e7be5c12317c04519a7bc8d0ef, this header is only
installed if opkg is built in its source tree (ie. ${B}=${S}). After that commit
the header will always be installed)

(From OE-Core rev: 3c6a8a39d820f14f9eb3df3d719cef2c469769da)

Signed-off-by: Paul Barker <paul@paulbarker.me.uk>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/opkg/opkg/obsolete_automake_macros.patch

@@ -1,15 +0,0 @@
-Upstream-Status: Pending
-
-Signed-off-by: Marko Lindqvist <cazfi74@gmail.com>
-diff -Nurd opkg/configure.ac opkg/configure.ac
---- opkg/configure.ac	2013-02-01 23:01:57.419774077 +0200
-+++ opkg/configure.ac	2013-02-01 23:02:25.643773458 +0200
-@@ -7,7 +7,7 @@
- AC_CONFIG_MACRO_DIR([shave])
-
- AM_INIT_AUTOMAKE
--AM_CONFIG_HEADER(libopkg/config.h)
-+AC_CONFIG_HEADERS(libopkg/config.h)
-
- AC_CANONICAL_HOST
- AC_GNU_SOURCE

meta/recipes-devtools/opkg/opkg_svn.bb

@@ -1,12 +1,10 @@
 require opkg.inc
 
-SRC_URI = "svn://opkg.googlecode.com/svn;module=trunk;protocol=http \
-           file://obsolete_automake_macros.patch \
-"
+SRC_URI = "svn://opkg.googlecode.com/svn;module=trunk;protocol=http"
 
 S = "${WORKDIR}/trunk"
 
-SRCREV = "650"
+SRCREV = "653"
 PV = "0.1.8+svnr${SRCPV}"
 
 PR = "${INC_PR}.0"