Remove unused Docker Swarm plugin

Author: chadlwilson

Rakefile

@@ -38,7 +38,6 @@ GO_PIPELINE_COUNTER = ENV['GO_PIPELINE_COUNTER'] || 0
 DOCKER_EA_PLUGIN_RELEASE_URL                = ENV['DOCKER_EA_PLUGIN_RELEASE_URL'] || 'https://api.github.com/repos/gocd-contrib/docker-elastic-agents/releases/latest'
 K8S_EA_PLUGIN_RELEASE_URL                   = ENV['K8S_EA_PLUGIN_RELEASE_URL'] || 'https://api.github.com/repos/gocd/kubernetes-elastic-agents/releases/latest'
 YUM_REPO_POLLER_PLUGIN_RELEASE_URL          = ENV['YUM_REPO_POLLER_PLUGIN_RELEASE_URL'] || 'https://api.github.com/repos/gocd/gocd-yum-repository-poller-plugin/releases/latest'
-DOCKER_SWARM_EA_PLUGIN_RELEASE_URL          = ENV['DOCKER_SWARM_EA_PLUGIN_RELEASE_URL'] || 'https://api.github.com/repos/gocd-contrib/docker-swarm-elastic-agents/releases/latest'
 ELASTICAGENTS_PLUGIN_RELEASE_URL            = ENV['ELASTICAGENTS_PLUGIN_RELEASE_URL'] || 'https://api.github.com/repos/gocd-contrib/elastic-agent-skeleton-plugin/releases/latest'
 DOCKER_REGISTRY_ARTIFACT_PLUGIN_RELEASE_URL = ENV['DOCKER_REGISTRY_ARTIFACT_PLUGIN_RELEASE_URL'] || 'https://api.github.com/repos/gocd/docker-registry-artifact-plugin/releases/latest'
 ANALYTICS_PLUGIN_DOWNLOAD_URL               = ENV['ANALYTICS_PLUGIN_DOWNLOAD_URL'] || 'https://api.github.com/repos/gocd/gocd-analytics-plugin/releases/latest'
@@ -150,7 +149,6 @@ namespace :plugins do
 
     sh "curl -sL --compressed -H \"Authorization: token #{GITHUB_TOKEN}\" --output target/go-server-#{VERSION_NUMBER}/plugins/external/elastic-agent-skeleton-plugin.jar #{download_url_from_latest_release(ELASTICAGENTS_PLUGIN_RELEASE_URL)}"
     sh "curl -sL --compressed -H \"Authorization: token #{GITHUB_TOKEN}\" --output target/go-server-#{VERSION_NUMBER}/plugins/external/docker-registry-artifact-plugin.jar #{download_url_from_latest_release(DOCKER_REGISTRY_ARTIFACT_PLUGIN_RELEASE_URL)}"
-    sh "curl -sL --compressed -H \"Authorization: token #{GITHUB_TOKEN}\" --output target/go-server-#{VERSION_NUMBER}/plugins/external/docker-swarm-elastic-agents-plugin.jar #{download_url_from_latest_release(DOCKER_SWARM_EA_PLUGIN_RELEASE_URL)}"
     sh "curl -sL --compressed -H \"Authorization: token #{GITHUB_TOKEN}\" --output target/go-server-#{VERSION_NUMBER}/plugins/external/docker-elastic-agents-plugin.jar #{download_url_from_latest_release(DOCKER_EA_PLUGIN_RELEASE_URL)}"
     sh "curl -sL --compressed -H \"Authorization: token #{GITHUB_TOKEN}\" --output target/go-server-#{VERSION_NUMBER}/plugins/external/k8s-elastic-agents.jar #{download_url_from_latest_release(K8S_EA_PLUGIN_RELEASE_URL)}"
     sh "curl -sL --compressed -H \"Authorization: token #{GITHUB_TOKEN}\" --output target/go-server-#{VERSION_NUMBER}/plugins/external/ldap_authorization_plugin.jar #{download_url_from_latest_release(LDAP_AUTHORIZATION_PLUGIN_DOWNLOAD_URL)}"