Makes PluginsFormatterTest pass

(cherry picked from commit 4a3806b)

Author: michaelklishin

deps/rabbitmq_cli/lib/rabbitmq/cli/formatters/plugins.ex

@@ -146,10 +146,22 @@ defmodule RabbitMQ.CLI.Formatters.Plugins do
     ]
   end
 
+  defp augment_version(%{version: version, running: nil}) do
+    to_string(version)
+  end
+
   defp augment_version(%{version: version, running: false}) do
     to_string(version)
   end
 
+  defp augment_version(%{version: version, running_version: nil}) do
+    to_string(version)
+  end
+
+  defp augment_version(%{version: version, running_version: ""}) do
+    to_string(version)
+  end
+
   defp augment_version(%{version: version, running_version: version}) do
     to_string(version)
   end

deps/rabbitmq_cli/test/plugins/plugins_formatter_test.exs

@@ -76,7 +76,7 @@ defmodule PluginsFormatterTest do
               enabled: :implicit,
               running: true,
               version: ~c"3.7.0",
-              running_version: nil
+              running_version: ""
             },
             %{
               name: :mock_rabbitmq_plugins_01,