Fix documentation distribution plugin

[fnegre]

installDist output is by default $buildDir/install/$project.name

Signed-off-by: Florian Nègre granini@gmail.com

Context

Contributor Checklist

• Review Contribution Guidelines
• Make sure that all commits are signed off to indicate that you agree to the terms of Developer Certificate of Origin.
• Check "Allow edit from maintainers" option in pull request so that additional changes can be pushed by Gradle team
• Provide integration tests (under <subproject>/src/integTest) to verify changes from a user perspective
• Provide unit tests (under <subproject>/src/test) to verify logic
• Update User Guide, DSL Reference, and Javadoc for public-facing changes
• Ensure that tests pass locally: ./gradlew <changed-subproject>:check

Gradle Core Team Checklist

• Verify design and implementation
• Verify test coverage and CI build status
• Verify documentation
• Recognize contributor in release notes

[blindpirate]

Thanks @fnegre !