Prevent printing token warning more than once

Mark warning of double tokens set when initially print to prevent
the warning from being shown multiple times during a single run.

plugins/commands/cloud/client/client.rb

@@ -6,6 +6,13 @@ require Vagrant.source_root.join("plugins/commands/cloud/errors")
 module VagrantPlugins
   module CloudCommand
     class Client
+      # @private
+      # Reset the cached values for scrubber. This is not considered a public
+      # API and should only be used for testing.
+      def self.reset!
+        class_variables.each(&method(:remove_class_variable))
+      end
+
       ######################################################################
       # Class that deals with managing users 'local' token for Vagrant Cloud
       ######################################################################
@@ -111,7 +118,9 @@ module VagrantPlugins
       # @return [String]
       def token
         if present?(ENV["VAGRANT_CLOUD_TOKEN"]) && token_path.exist?
-          @env.ui.warn <<-EOH.strip
+          # Only show warning if it has not been previously shown
+          if !defined?(@@double_token_warning)
+            @env.ui.warn <<-EOH.strip
 Vagrant detected both the VAGRANT_CLOUD_TOKEN environment variable and a Vagrant login
 token are present on this system. The VAGRANT_CLOUD_TOKEN environment variable takes
 precedence over the locally stored token. To remove this error, either unset
@@ -120,6 +129,8 @@ the VAGRANT_CLOUD_TOKEN environment variable or remove the login token stored on
     ~/.vagrant.d/data/vagrant_login_token
 
 EOH
+            @@double_token_warning = true
+          end
         end
 
         if present?(ENV["VAGRANT_CLOUD_TOKEN"])

test/unit/plugins/commands/cloud/client_test.rb

@@ -24,6 +24,7 @@ describe VagrantPlugins::CloudCommand::Client do
   end
 
   after do
+    described_class.reset!
     Vagrant::Util::CredentialScrubber.reset!
   end
 
@@ -192,7 +193,7 @@ describe VagrantPlugins::CloudCommand::Client do
     let(:path_exists) { false }
 
     before do
-      expect(subject).to receive(:token).and_call_original
+      allow(subject).to receive(:token).and_call_original
       allow(subject).to receive(:token_path).and_return(token_path)
       allow(token_path).to receive(:exist?).and_return(path_exists)
     end
@@ -215,6 +216,11 @@ describe VagrantPlugins::CloudCommand::Client do
           expect(env.ui).to receive(:warn)
           subject.token
         end
+
+        it "should only print warning of two tokens once" do
+          expect(env.ui).to receive(:warn).with(/detected/).once
+          3.times { subject.token }
+        end
       end
     end