Updating example.clj for kindergarten-garden

The solution for this example was incorrect. The offending line in the original was line 7

    (clojure.string/split row-string #"")

This doesn't give the expected result. Example:

    (clojure.string/split "ABC" #"")

Result:

    ["" "A" "B" "C"]
using namespaces consistently.
Fixed remaining example for namespace.