create_core command gives confusing messages if broken config is given, fixed, given again

If the config used to create a core, the command complains and aborts:

Example:

$ bin/solr create_core -c minicore -d ../miniconf/

Creating new core 'minicore' using command:
http://localhost:8983/solr/admin/cores?action=CREATE&name=minicore&instanceDir=minicore

ERROR: Error CREATEing SolrCore 'minicore': Unable to create core [minicore] Caused by: The element type "dynamicField" must be terminated by the matching end-tag "</dynamicField>".

However, after fixing the problem, trying to re-run the command gives the same error, causing all sorts of confusion.

What actually happened is that config has been copied to the destination directory and then when the command is run the second time, it does not recopy fresh - and fixed - files, but just reuses the previously copied - broken - ones.

The workaround is to manually delete created destination directory and rerun the command. But it is far from obvious.

The fix would be either undoing the copy - a delete. The minimal fix would be a log statement that the directory was copied (which would help example logs too). And perhaps an extra message when the create command failed that files were copied and may need to be manually deleted.