Python2 port is missing git information and uses the wrong platform toolset

When installing the python2 port, a few calls to `git` are made within the build:

```
git name-rev --name-only HEAD
git rev-parse --short HEAD
git describe --all --always --dirty
```

Since the port is downloaded as a zip file without additional git information (concretely, the `.git` directory), `git` will start traversing directories up in the tree looking for `.git`. In an environment with restricted access, this will hit `vcpkg`'s `.git` and attempt to write the `index.lock`, leading to a restricted write.

It also attempts to build using `PLATFORM_TOOLSET` set to the default of `VCPKG_PLATFORM_TOOLSET`, which could be `v141`. The officially supported value is `v140`.