gnucash maint: Fix test-backend-dbi for Postgress and MySQL.

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash/commit/de927d53 (commit)
	from  https://github.com/Gnucash/gnucash/commit/c2972c75 (commit)



commit de927d535d38fc584659fdea3935ea9834dab34b
Author: John Ralls <jralls at ceridwen.us>
Date:   Fri Jul 13 16:34:42 2018 -0700

    Fix test-backend-dbi for Postgress and MySQL.
    
    Pass MySQL database exists errors and skip creating the database
    if it exists.



Summary of changes:
 libgnucash/backend/dbi/gnc-backend-dbi.cpp | 9 ++++++++-
 po/POTFILES.in                             | 1 -
 2 files changed, 8 insertions(+), 2 deletions(-)