(puppetlabsGH-1846) Wrap all powershell commands in a script

Powershell will [exit 1](PowerShell/PowerShell#11461) whenever the
$LASTEXITCODE is greater than 0, regardless of what the code is,
whenever running a bare command. Powershell exits with the correct exit
code when executing files, or when `exit $LASTEXITCODE` is appended to
the command being run (as in the [execute_process
snippet](https://github.com/puppetlabs/bolt/blob/0d44ce739d4dafcb6d27abd894e230894fdd50e0/lib/bolt/shell/powershell/snippets.rb#L19),
meaning this is only an issue when running commands using the local
transport through Bolt. This modifies the local transport to append `;
exit $LASTEXITCODE` to commands run on Windows, which will correctly
return the exit code from the command run instead of changing it to 1.

Closes puppetlabs#1846

!bug

* **Return correct exit code when running commands in powershell** ([1846](puppetlabs#1846))

  Bolt will now display the correct exit code when running commands in
  powershell that exit with code > 1.

lib/bolt/transport/local/connection.rb

@@ -47,6 +47,7 @@ def copy_file(source, dest)
 
         def execute(command)
           if Bolt::Util.windows?
+            command += '; exit $LASTEXITCODE'
             # If it's already a powershell command then invoke it normally.
             # Otherwise, wrap it in powershell.exe.
             unless command.start_with?('powershell.exe')

spec/integration/local_spec.rb

@@ -33,6 +33,12 @@
       expect(result[0]['_error']).to be
     end
 
+    it 'returns correct exit code' do
+      result = run_failed_nodes(%W[command run exit(2) --targets #{uri} --format json]).first
+      expect(result['_error']['msg']).to eq('The command failed with exit code 2')
+      expect(result['_error']['details']['exit_code']).to eq(2)
+    end
+
     it 'runs a ruby task using bolt ruby', :reset_puppet_settings do
       result = run_one_node(%w[task run sample::bolt_ruby message=somemessage] + config_flags)
       expect(result['env']).to match(/somemessage/)