dataIndentationChars disregarded if empty string

[Svetoslav Nedkov]

Steps to reproduce

1. Set

   CKEDITOR.config.dataIndentationChars = '';
   

2. Insert a table in editor, this will create several nested tags that will demonstrate the problem.
3. Check HTML source, see that indentation is still present.

Expected result

I'm leaning on the documentation for this configuration variable (​http://docs.ckeditor.com/#!/api/CKEDITOR.config-cfg-dataIndentationChars):

// No indentation.
CKEDITOR.config.dataIndentationChars = '';

Actual result

Indentation is still present.

Other details (browser, OS, CKEditor version, installed plugins)

Firefox, Linux, latest master branch from repository.