gnucash maint: Install the current, 2015, and 2016 ChangeLogs.

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash/commit/350dd690 (commit)
	from  https://github.com/Gnucash/gnucash/commit/3bc0241e (commit)



commit 350dd690fd97ae302a1878b035f8206bfa386c7d
Author: John Ralls <jralls at ceridwen.us>
Date:   Wed Sep 6 11:43:43 2017 -0700

    Install the current, 2015, and 2016 ChangeLogs.



Summary of changes:
 CMakeLists.txt | 4 ++++
 1 file changed, 4 insertions(+)