start_sprint.sh pulls phpmyadmin (bad in tight internet situation)

[rfay]

The idea behind quicksprint is to bundle everything up and prevent dependency on conference wifi.

I note that start_sprint.sh pulls phpmyadmin the first time. It should have it bundled.

[rfay]

There are two components to the fix here:

1. Upstream (ddev) Specify the version of phpmyadmin
2. Here: Make sure we have phpmyadmin in the list of images to grab from the tarball.