allows integrations core to download jmx fetch from rakefile (#3419)

* allows integrations core to download jmx fetch from rakefile

* fixes import error

* lint

Rakefile

@@ -46,9 +46,11 @@ end
 desc 'Grab libs'
 task 'setup_libs' do
   in_venv = system "python -c \"import sys ; exit(not hasattr(sys, 'real_prefix'))\""
-  raise 'Not in dev venv/CI environment - bailing out.' if !in_venv && !ENV['CI']
+  raise 'Not in dev venv/CI environment/Integrations - bailing out.' if !in_venv && !ENV['CI'] && !ENV['SDK_HOME']
 
-  jmx_version = `python -c "import config ; print config.JMX_VERSION"`
+  Rake::Task['setup_env'].invoke
+
+  jmx_version = `venv/bin/python -c "import config ; print config.JMX_VERSION"`
   jmx_version = jmx_version.delete("\n")
   puts "jmx-fetch version: #{jmx_version}"
   jmx_artifact = "jmxfetch-#{jmx_version}-jar-with-dependencies.jar"