clojure.java.jdbc 0.3.x and 0.2.x compatibility.

clojure.java.jdbc 0.3.x has a "deprecated" namespace
that contains all the functions from 0.2.x for
compatibility. This change makes ragtime
work with both versions by attempting to require
the deprecated namespace (0.3.x) first and falling
back to the top level namespace if it doesn't
exist, thereby assuming 0.2.x.

Kinda janky, but does keep ragtime working with projects
stuck on 0.2.x without preventing newer projects from using
it.