Make CommandLine in AutoComplete use correct IFactory implementation

In some cases using the DefaultFactory when instantiating CommandLine
could cause subcommands that require a specific IFactory
implementation to fail to be created. This commit makes the
CommandLine instance created by AutoComplete command use the
IFactory passed to the command (if any).

src/main/java/picocli/AutoComplete.java

@@ -137,7 +137,7 @@ public Integer call() {
                 }
                 Class<?> cls = Class.forName(commandLineFQCN);
                 Object instance = factory.create(cls);
-                CommandLine commandLine = new CommandLine(instance);
+                CommandLine commandLine = new CommandLine(instance, factory);
 
                 if (commandName == null) {
                     commandName = commandLine.getCommandName(); //new CommandLine.Help(commandLine.commandDescriptor).commandName;