classes/buildhistory: write out files in UTF-8 format

classes/buildhistory: write out files in UTF-8 format

If the package information contained unicode characters (for example, in
the package file listing) then writing them out as ASCII would fail, so
write them out using codecs.open() instead of open() using UTF-8. This
fixes ca-certificates failing in do_packagedata when buildhistory is
enabled.

(From OE-Core rev: dcf228fe69bfee4e22baad477ad407248c0f9cdb)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>