Fix prefix check as per MySql bug report 93073

[tipstrade]

See https://bugs.mysql.com/bug.php?id=93073

I signed and submitted the OCA on the 5th November 2018.

[mysql-oca-bot]

Hi, thank you for submitting this pull request. In order to consider your code we need you to sign the Oracle Contribution Agreement (OCA). Please review the details and follow the instructions at http://www.oracle.com/technetwork/community/oca-486395.html
Please make sure to include your MySQL bug system user (email) in the returned form.
Thanks

[tipstrade]

I have signed and submitted the OCA, but have received no response as to whether it's even been received by Oracle. has been received and hopefully has been confirmed at this stage, as TipsTrade Ltd.

[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

[tipstrade]

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=93073 for updates.
Thanks