Get version of an unversionned plugin to use with Mojo Executor

MojoExecutorUtils1.java

    /**
     * Creates a plugin from source one with version set according to project dependency management and other rules ..
     * @param environment
     * @param plugin
     * @return
     */
    private static Plugin findVersionOf(MavenEnvironment environment, final Plugin plugin) {
        SortedSet<Plugin> candidates = new TreeSet<Plugin>();
        if(plugin.getVersion()!=null)
            return plugin;
        Iterable<Plugin> plugins = Iterables.concat(environment.project.getPluginManagement().getPlugins(), environment.project.getBuildPlugins());
        Iterable<Plugin> matching = Iterables.filter(plugins, new Predicate<Plugin>() {

            @Override
            public boolean apply(Plugin input) {
                return input.getArtifactId().equals(plugin.getArtifactId()) && input.getGroupId().equals(plugin.getGroupId());
            }});
        Plugin found = Iterables.getFirst(matching, null);
        if(found==null)
            throw new UnsupportedMavenPluginException("plugin "+plugin+" isn't declared in this project. You should set its version by hand !");
        return found;
    }