gnucash-docs maint: Add backslashes on cmake entries in EXTRA_DIST

[Frank H.Ellenberger]

Updated	 via  https://github.com/Gnucash/gnucash-docs/commit/ac64a672 (commit)
	from  https://github.com/Gnucash/gnucash-docs/commit/f77e8a38 (commit)



commit ac64a6726c35f4e42ed86f797b1e617c1c69a100
Author: Frank H. Ellenberger <frank.h.ellenberger at gmail.com>
Date:   Mon Sep 9 08:20:31 2019 +0200

    Add backslashes on cmake entries in EXTRA_DIST



Summary of changes:
 Makefile.am | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)