test: use mongodb-3.2 on Travis (#369)
test: use mongodb-3.2 on Travis (#369)

The default version is 2.6, which is simply too old for some of the
features used in the tests.

Signed-off-by: Ryan Graham <cdcde8092c3401c6195519cb357ce33fe9f16916@gmail.com>
Tuxity/loopback-connector-mongodb