* Add python check for pip resource
When checking pip resources, we should skip resource if python is not
installed or we will fail with an error when trying to parse the path.
* Check pip command on windows
On Windows, if pip has a newer version available, it adds an error
message to stderr. Now checking if both stderr and stdout on windows
have values. If so, assume pip package is installed.
* Clean up powershell query command
- Make it easier to read what the powershell command is doing
- Make it easier to read what the cmd_successful method lokos for
Signed-off-by: Paul Welch <pwelch@chef.io>
