opkg: Update svn 625 -> 633 and fix preinst issues

There is a major issue with opkg images at the moment as preinst
functions are not being executed before their dependencies are installed
and this is leading to corruption of images containing avahi/dbus in
particular.

There are various changes in upstream opkg in the last 8 revisions which
make changes in this area but sadly these aren't enough to get things
working for us. I've updated to the latest svn revision with this patch
since it makes sense to pull in those changes first and then supplement
them with the attached patches.

There is a full description of the patches in the patch headers but in
summary they:

a) Ensure preinst functions execute with their dependencies installed.
   This is a pretty invasive change as it changes the package install
   ordering in general.
b) Ensure opkg sets $D, not $PKG_ROOT which we don't use
c) Change opkg to allow execution of postinstall functions which fail
   resulting in execution on the target device as rootfs_ipk.bbclass
   currently does manually.

The remaining changes interface this with the rest of the OE build
infrastructure, adding in the option to tell opkg to run the preinst and
postinst functions, ensure the correct environment is present for the
postinst scripts and removing the now unneeded rootfs_ipk class code
which opkg now does itself.

[YOCTO #1711]

(From OE-Core rev: 2feba313c991170747381c7cf821a45c2cd04632)

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

meta/classes/package_ipk.bbclass

@@ -133,7 +133,7 @@ package_install_internal_ipk() {
 
 	mkdir -p ${target_rootfs}${localstatedir}/lib/opkg/
 
-	local ipkg_args="-f ${conffile} -o ${target_rootfs} --force-overwrite"
+	local ipkg_args="-f ${conffile} -o ${target_rootfs} --force-overwrite --force_postinstall"
 
 	opkg-cl ${ipkg_args} update