Apply upstream patch to filter virt-what warnings from virtual fact
With the additional requirement of virt-what that was added in
facter-1.6.18-1, the virtual fact was incorrect when facter was not run
by root:
$ facter | egrep '^(facterversion|virtual)'
facterversion => 1.6.18
virtual => virt-what: this script must be run as root
This is upstream ticket #19989¹. It was applied to the 1.7.x branch².
¹ https://projects.puppetlabs.com/issues/19989
² https://github.com/puppetlabs/facter/commit/b7784a3