mariadb-tzinfo-to-sql generates superfluous warnings

This is an update to MDEV-14224, which was mistakenly Closed as "Not a Bug".

Either of the following commands:

    mariadb-tzinfo-to-sql /usr/share/zoneinfo > /dev/null

    mysql_tzinfo_to_sql   /usr/share/zoneinfo > /dev/null

generate the following superfluous warnings:

    Warning: Unable to load '/usr/share/zoneinfo/leap-seconds.list' as time zone. Skipping it.

    Warning: Unable to load '/usr/share/zoneinfo/leapseconds' as time zone. Skipping it.

    Warning: Unable to load '/usr/share/zoneinfo/tzdata.zi' as time zone. Skipping it.

The first file is installed by Debian and the other two are standard tzdata files.
They should not generate warnings unless verbose > 0.

Attached is a patch which silently skips the following standard files
(unless verbose > 0):

• iso3166.tab
• leap-seconds.list
• leapseconds
• tzdata.zi
• zone.tab
• zone1970.tab

Thank you!
Daniel Lewart
Urbana, Illinois