Simplify tui_data_win::erase_data_content

There's only a single call to tui_data_win::erase_data_content now, so
remove the parameter and make it just render the "empty window" text.

Tested-By: Tom de Vries <tdevries@suse.de>
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Approved-By: Andrew Burgess <aburgess@redhat.com>
2 files changed