gnucash maint: Remove unused ifdefs for IMPLEMENT_BOOK_DOM_TREES_LATER.

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash/commit/456ab224 (commit)
	from  https://github.com/Gnucash/gnucash/commit/a0a0ffbb (commit)



commit 456ab2241f8e5532c1b6724fc43c77e06d32fab5
Author: John Ralls <jralls at ceridwen.us>
Date:   Fri Jul 26 16:17:09 2019 -0700

    Remove unused ifdefs for IMPLEMENT_BOOK_DOM_TREES_LATER.
    
    Apparently stub code for a different way of generating the DOM tree, never implemented.



Summary of changes:
 libgnucash/backend/xml/gnc-book-xml-v2.cpp | 65 ------------------------------
 libgnucash/backend/xml/io-gncxml-v2.cpp    | 25 ------------
 2 files changed, 90 deletions(-)