fix escaping of powershell variable

As this is nested in a powershell variable $command, it must be escaped
otherwise it is evaluated when the variable is created, giving an error that
"The term 'True' is not recognized as the name of a cmdlet, function,
script". This prevented using a puppet.working_directory on Windows.
Merge pull request #4059 from brettporter/windows-puppet-wd

Unable to use puppet.working_directory on Windows
Removed extra n from the word "connection"

Removed extra n from the word "connection" in "Attempting SSH connection" in logger call.
Merge pull request #4120 from jdmulloy/fix_ssh_typo

Removed extra n from the word "connection"
Fix spelling of Chef Solo, Chef Client, and Chef Server in website docs
Merge pull request #4126 from mitchellh/chef-server-grammar-fixes

Fix spelling of Chef Solo, Chef Client, and Chef Server in website docs
VirtualBox driver should replace only last occurence of suggested VM name.
Ensure VirtualBox virtual disks are stored in the correct directory on Windows hosts
Ensure VirtualBox virtual disks are stored in the correct directory round 2
Merge pull request #4133 from keiths-osc/windows_virtualbox_vmdk_path_fix

Ensure VirtualBox virtual disks are stored in the correct directory on Windows hosts
Fixed issue 4161

Wrong varaible name was used to try and delete the existing Vagrantfile causing an error.
Merge pull request #4162 from mitchellh/fix-issue-4161

Fixed issue 4161