"The working folder is already in use" when changing checkout directory from root of the plan to its subdir

[Sergey Podobry]

Steps to reproduce:

1. Create a plan with empty checkout directory (checkout to the root of the plan)
2. Run the build
3. Change the checkout directory for example to 'subdir' (checkout to the subdir of the plan)
4. Run the build <-- error occurs

Also the bug is reproduced if checking out to the subdir first and then to the root.

Cause:

The plugin checked only exact mappings. If a workspace is located in the directory one level up or down it is not detected.

Linked issues: #35

[Sergey Podobry]

Fixed in 1.1.7 and 1.0.16.