grails plugin should check whether groovy plugin is already applied in 3.2.0

[musketyr]

Steps to Reproduce

1. Create new directory master-project
2. Create build file with content subprojects { apply plugin: 'groovy' }
3. Create build settings file with content include 'child-project'
4. Run grails create-app child-project assuming you have Grails 3.2.0 present on PATH
5. Try run gradle :child-project:bootRun assuming you have Gradle 2.14.1 present on PATH
6. You got error message Error:(21, 0) Cannot add task ':child-project:groovydoc' as a task with that name already exists.

Expected Behaviour

If the groovy Gradle plugin is already applied the Grails application which is a suproject should not try to add it again.

Actual Behaviour

The Gradle build fails with

* What went wrong:
A problem occurred evaluating project ':child-project'.
> Failed to apply plugin [id 'org.grails.grails-web']
   > Cannot add task ':child-project:groovydoc' as a task with that name already exists.

Environment Information

• Operating System: darwin15 (OS X El Captan)
• Grails Version: 3.2.0
• JDK Version: Java(TM) SE Runtime Environment (build 1.8.0_92-b14)

Example Application

• https://github.com/musketyr/groovy-plugin-from-parent-in-grails

[musketyr]

Thanks!