unbound_version fact needs a test

[zachfi]

$ /usr/local/sbin/unbound -V 2>&1
Version 1.9.3

Configure line: --with-ssl=/usr --with-libexpat=/usr/local --disable-dnscrypt --disable-dnstap --enable-ecdsa --disable-event-api --enable-gost --with-libevent --disable-subnet --disable-tfo-client --disable-tfo-server --with-pthreads --prefix=/usr/local --localstatedir=/var --mandir=/usr/local/man --infodir=/usr/local/share/info/ --build=amd64-portbld-freebsd12.0
Linked libs: libevent 2.1.11-stable (it uses kqueue), OpenSSL 1.1.1a-freebsd  20 Nov 2018
Linked modules: dns64 respip validator iterator

BSD licensed, see LICENSE in source package for details.
Report bugs to unbound-bugs@nlnetlabs.nl or https://github.com/NLnetLabs/unbound/issues

A fixture such as this should be able to catch the issue I'm currently running into.

Error: Facter: error while resolving custom facts in /var/puppet/lib/facter/unbound_version.rb: undefined method `[]' for nil:NilClass

[b4ldr]

these got added in #212