view_alter #theme suggestion forces views using 'rendered entity' to use message.tpl.php and ignore other theme_hook_suggestions

When rendering a message in a view using Rendered Entity, the message_message_view_alter function sets the build #theme key to 'message' which in turn set the 'theme_hook_suggestion' to 'message' and overrides any alternate bundle templates

This patch resolves that by checking for a #bundle key in the build and applying an alternate #theme value if it exists.