Disable Parallels Desktop feature "--tools-autoupdate"

[legal90]

Fixes the following issues:

• Updating Tools takes forever #281
• Parallels: hitting dpkg issue again (see desc) chef/bento#695

The details are explained in this comment: #281 (comment)

TL;DR: We should disable the built-in Parallels Desktop feature of auto-updating Parallels Tools in VMs because it collides with the similar feature managed by our Vagrant provider and could cause provision failures.

If you want to keep Parallels Tools in your VMs up-to-date, please, enable an appropriate provider feature:

config.vm.provider "parallels" do |prl|
  prl.update_guest_tools = true
end

cc: @romankulikov