hob now uses both a pre and post file, update the wrapper script to generate
and use both of these.
Addresses [YOCTO #1281]
(From OE-Core rev: b68f90b765e7c8923033ee7ff7746f39a2e91ff7)
Signed-off-by: Joshua Lock <josh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>