v1.2.0.rc2 - Port Forwarding & Import fixes

Fixes (only for Parallels Desktop 10, which is in closed beta):

• Forwarded ports are cleaned before VM suspend and restored before VM resume.
• Collision of forwarded ports can be repaired in resume as well (unlike VirtualBox, which has a known issue hashicorp/vagrant#1740)

Enhancement:

• Added regen_box_uuid customization option, which is true by default.
  Being forced to false, this option disables an automatic regeneration of box UUID. In this case the SMBIOS UUID of each new VM will be copied from the box (template). It allows to save the activation status of Windows-based virtual machines.

Requested by #113 (comment)

How to use:

config.vm.provider "parallels" do |v|
    v.regen_box_uuid = false
end