-o option conflicts with namespace when generating lua code.

[wxjcug]

flatc.exe --lua -o lua schema.fbs

if there is a namespace declaration in the firtst line of schema.fbs, it will generate two empty folders with out any code.

[beingbrijesh]

@wxjcug I have identified the issue and also created a PR and I don't know when it will be reviewed so you can follow the given fix

• Use ConCatPathFileName(options_.output_path, path) and EnsureDirExists(full_dir) so generators create namespace directories under the provided -o path.