Bug 15290: (follow-up)SQL reports headers encoding problem

Bug 15290: (follow-up)SQL reports headers encoding problem

Fix SQL row data and headers enconding problem

To test:
-Apply patches
-Follow previous test plan
-Notice the headers and row data is displayed in UTF-8
 without double encoding
-Save in Comma separated text, Tab seprated text, and Open Document.
-Verify in the three options the file exported is Ok

Signed-off-by: Frédéric Demians <f.demians@tamil.fr>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>