gnucash maint: Fix reference to SVN in README.

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash/commit/d658b757 (commit)
	from  https://github.com/Gnucash/gnucash/commit/1ef17e6e (commit)



commit d658b7570c80eeaa535ebb627a5c168aaabbcfea
Author: John Ralls <jralls at ceridwen.us>
Date:   Sun Dec 18 12:50:30 2016 -0800

    Fix reference to SVN in README.



Summary of changes:
 README | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)