Checked if uninstaller removed its directory.

[excitoon]

Sometimes uninstaller removes its own directory by itself. In these cases scoop fails uninstallation process with the following error:

PS C:\Users\Chebotarev_V\scoop\apps\scoop\current> scoop uninstall flux
Uninstalling 'flux' (4.66).
Running uninstaller... done.
Removing shim for 'flux'.
Unlinking ~\scoop\apps\flux\current
ERROR Couldn't remove '~\scoop\apps\flux\4.66'; it may be in use.

Example:

scoop bucket add user https://github.com/excitoon/scoop-user.git
scoop install user/flux

This patch fixes it.