Fix error when clicking 'Go' and having an empty textarea in SQL tab.

Signed-off-by: Hugues Peccatte <hugues.peccatte@gmail.com>
Fix coding style

Signed-off-by: Ann + J.M <phpMyAdmin@ZweiSteinSoft.de>
Translated using Weblate (Azerbaijani)

Currently translated at 29.7% (824 of 2770)
Translated using Weblate (Korean)

Currently translated at 82.1% (2276 of 2770)
Translated using Weblate (Norwegian Bokmål)

Currently translated at 61.5% (1705 of 2770)
Merge remote-tracking branch 'origin/QA_4_2' into QA_4_2
Fix failing tests

Signed-off-by: Ann + J.M <phpMyAdmin@ZweiSteinSoft.de>
Merge pull request #1247 from Tithugues/QA_4_2_fixEmptySQL

Fix error when clicking 'Go' and having an empty textarea in SQL tab. (bug #4470)
Update ChangeLog.

Signed-off-by: Hugues Peccatte <hugues.peccatte@gmail.com>