fix(inspec): the package name for Arch is openssh

For Arch, Inspec define `platform[:family]` as `linux` and
`platform[:name]` as `arch`.

test/integration/default/controls/packages_spec.rb

 # Overide by Platform
 package_name =
   case platform[:family]
-  when 'suse'
+  # `linux` here is sufficient for `arch`
+  when 'suse', 'linux'
     'openssh'
   else
     'openssh-server'