mysql_tzinfo_to_sql: suppress expected warnings

[dveeden]

See also https://bugs.mysql.com/bug.php?id=115019

Before:

$ mysql_tzinfo_to_sql /usr/share/zoneinfo/ | wc -l
Warning: Unable to load '/usr/share/zoneinfo//iso3166.tab' as time zone. Skipping it.
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.
Warning: Unable to load '/usr/share/zoneinfo//zone.tab' as time zone. Skipping it.
Warning: Unable to load '/usr/share/zoneinfo//zone1970.tab' as time zone. Skipping it.
138261

After:

$ mysql_tzinfo_to_sql /usr/share/zoneinfo/ | wc -l
138261

Another way would be to check the file magic, which should be TZif starting at byte 0 for timezone files according to /usr/share/magic.

[mysql-oca-bot]

Hi, thank you for your contribution. Please confirm this code is submitted under the terms of the OCA (Oracle's Contribution Agreement) you have previously signed by cutting and pasting the following text as a comment:
"I confirm the code being submitted is offered under the terms of the OCA, and that I am authorized to contribute it."
Thanks

[dveeden]

I confirm the code being submitted is offered under the terms of the OCA, and that I am authorized to contribute it.

[mysql-oca-bot]

Hi, thank you for your contribution. Your code has been assigned to an internal queue. Please follow
bug http://bugs.mysql.com/bug.php?id=115021 for updates.
Thanks