gnucash maint: Multiple changes pushed

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash/commit/9bfaada3 (commit)
	 via  https://github.com/Gnucash/gnucash/commit/1116ce90 (commit)
	from  https://github.com/Gnucash/gnucash/commit/267852ba (commit)



commit 9bfaada356e5fb8ec58347b50e96de1884797f5d
Author: John Ralls <jralls at ceridwen.us>
Date:   Fri Dec 28 13:21:16 2018 -0800

    Bug 796961 - Can't overwrite existing MYSQL database, V3.3.
    
    Because m_exists was left true after dropping it, so the new
    database wasn't created.

commit 1116ce909b9827ac928ed41d68c58190a62f4546
Author: John Ralls <jralls at ceridwen.us>
Date:   Fri Dec 28 13:16:41 2018 -0800

    Bug 796967 - gnclock table not removed when using PostgreSQL.
    
    Because of https://sourceforge.net/p/libdbi-drivers/bugs/24.
    This issue causes trouble in save_may_clobber_data() as well, so
    work around it by using a SQL query instead of dbi_conn_get_table_list.



Summary of changes:
 libgnucash/backend/dbi/gnc-backend-dbi.cpp     | 59 ++++++++++++++++++++++----
 libgnucash/backend/dbi/gnc-dbiproviderimpl.hpp | 37 ++++++++++------
 2 files changed, 74 insertions(+), 22 deletions(-)