Update phpMyAdmin to 4.2.13.1

4.3.1 is out, but I haven't done any testing with that. Let's
go with 4.2.13.1 and then push to 4.3.1 after we ship
Merge pull request #520 from Varying-Vagrant-Vagrants/phpmyadmin-update

[PR] Update phpMyAdmin to 4.2.13.1