Bugfix / DBD::mysql version restriction in release/95

Created by: mkszuba

Description

A so far unidentified change made in version 4.050 causes dbConnection.t tests checking if database ping returns an undef with disconnect_when_inactive(1) to fail. Prevent installation of that (or newer) version of DBD::mysql until we have had a chance to debug the issue. Yes, this is very much a stopgap measure.

Use case

Both Travis and users who rely on our cpanfiles to install DBD::mysql currently end up with a version which fails tests, and possibly does not in fact disconnect from the database when inactive.

Benefits

DBD::mysql-4.050 is brand-new so for the time being, having this restriction in place should keep things chugging along until we have actually fixed this.

Possible Drawbacks

Will likely fail spectacularly once new versions od DBD::mysql have made it into distros and so on. Merely bypasses the issue rather than fixing it.

Testing

Have you added/modified unit tests to test the changes? no

If so, do the tests pass/fail? N/A

Have you run the entire test suite and no regression was detected? Have run dbConnection.t before and after the change. The three ping() failures go away, no new ones appear.