Arm install fails if torctl in path

When you run arm's install script it...

• checks if TorCtl is available and, if not, prompts the user to get a copy
• copies all the modules, including TorCtl, to the installation destination

If the user has python-torctl installed then we skip fetching a local copy of torctl (since it's already available externally), then setup.py fails to copy a 'src/TorCtl' module since it's not contained within arm itself.

Issue caught by DustyDingo