commmands/box/remove: fix exception when no provider specified [GH-2100]

CHANGELOG.md

@@ -30,6 +30,8 @@ IMPROVEMENTS:
   - core: "config.vm.host_name" works again, just an alias to hostname.
   - core: Reboots via SSH are now handled gracefully (without exception).
   - core: Mark `disabled` as true on forwarded port to disable. [GH-1922]
+  - commands/box/remove: Fix stack trace that happens if no provider
+    is specified. [GH-2100]
   - commands/plugin/install: Post install message of a plugin will be
     shown if available. [GH-1986]
   - commands/status: cosmetic improvement to better align names and

plugins/commands/box/command/remove.rb

@@ -26,7 +26,7 @@ module VagrantPlugins
             if providers.length > 1
               @env.ui.error(
                 I18n.t("vagrant.commands.box.remove_must_specify_provider",
-                       name: args[0],
+                       name: argv[0],
                        providers: providers.join(", ")))
               return 1
             end