First Boot Package Install now includes installation error reporting

I'm updating the copy of First Boot Package Install included with
create_vmware_osx_install_dmg, as part of following up on a First Boot
Package Install pull request by Matthew Kweskin
(https://github.com/mkweskin), I've updated First Boot Package install
so that it now reports whether an installation has succeeded or failed.
This error reporting is in addition to the error logging that is added
to /var/log/install.log by OS X's installer tool.