DFID r4d rule retains the original path

Change the rule so that it keeps the capitalisation of the URL requested.
Incidentally, it will now keep anything else about the path that was changed by
canonicalisation.

The immediate need for this is to get a smokey test passing. The smokey test
expects that the capitalisation of the redirect matches the input. The test is
this one:
https://github.com/alphagov/redirector/blob/5481ae103aae8d9ec97c78c2f3df0a3d9c9177d0/data/tests/popular.csv#L912
Clarify comment about the test database
Make CI builds more reliable

This fixes the following scenario:
 1) schema change made in Transition app to the shared database
 2) bouncer depends on this schema change, but is building on a box which hasn't
    run that schema change yet
 3) bouncer build fails

We already use db/structure.sql for Travis builds, let's use it for CI too.

This does highlight that db/structure.sql can become out of date. That's a
problem for another day.
Fix broken jenkins.sh
Restore old travis config
Fix jenkins.sh
Use the correct user