If the project working directory is not customised, it will end up being
${grails.work.dir}/projects/workspace, since "workspace" is usually the working
directory in Hudson. This makes it difficult to build multiple Grails projects
in one Hudson instance.

The plugin should by default change grails.project.work.dir to be named after
the project, which makes more sense.

(Two workarounds for this problem: check out the source in a subdirectory of
the workspace, or change the workspace directory under Advanced Project Options
-> Use custom workspace.)