Fixing Akonadi’s warning of the non-existing leap second table

“Ever since I installed Kontact 4.5, it has been showing an
MySQL warning when starting. The exact error in the logs is:

Can’t open and lock time zone table: Table
‘mysql.time_zone_leap_second’ doesn’t exist trying to live without

While it’s only a warning, I don’t like to have my logs filled
with warnings. Hence, I went on a hunt to prevent this warning.
Lots of posts said this issue is fixed in newer versions (certainly
not for me!), or it doesn’t matter. But that wasn’t good enough for
me, so I felt relieved when I found a workaround yesterday, which I
shall explain below.”