(PUP-8766) Enable early pluginsync for puppet device agent mode

When running `puppet device` in agent mode, a pluginsync needs to happen
before the device is loaded. For the non-agent modes `--facts`,
`--resource`, and `--apply`, doing no pluginsync is useful since they are
used in local workflows (like testing), and for a quicker turnaround when
exploring devices.

Author: DavidS

lib/puppet/application/device.rb

@@ -1,4 +1,5 @@
 require 'puppet/application'
+require 'puppet/configurer'
 require 'puppet/util/network_device'
 
 class Puppet::Application::Device < Puppet::Application
@@ -256,6 +257,9 @@ def main
           Puppet[:vardir] = ::File.join(Puppet[:devicedir], device.name)
           Puppet[:certname] = device.name
 
+          unless options[:resource] || options[:facts] || options[:apply]
+            Puppet::Configurer::PluginHandler.new.download_plugins(env)
+          end
           # this init the device singleton, so that the facts terminus
           # and the various network_device provider can use it
           Puppet::Util::NetworkDevice.init(device)

spec/unit/application/device_spec.rb

@@ -504,7 +504,9 @@
         expect { @device.main }.to exit_with 1
       end
 
-      it "should print the device url scheme, host, and port" do
+      it "should retrieve plugins and print the device url scheme, host, and port" do
+        Puppet.stubs(:info)
+        Puppet.expects(:info).with "Retrieving pluginfacts"
         Puppet.expects(:info).with "starting applying configuration to device1 at ssh://testhost"
         Puppet.expects(:info).with "starting applying configuration to device2 at https://testhost:443/some/path"
         expect { @device.main }.to exit_with 1