Comment 8 for bug 234609

This appears to me to not necessarily be a straightforward fix necessarily. My reading of this is that if you have php5-mysql or php5-pgsql already installed but then choose the other one in the moodle install configuration you end up with problems.

I don't think there is any dependence issue really here from how I read this, but rather an issue with the debconf questions asked during install.

The only thing I can think of to get around that would be to check what database the user has installed and only ask them to choose if they have both installed, otherwise we just go with the one they have installed. Does that make sense?