travis: fix provisioning
travis: fix provisioning

Upstart has some difficulties to start the server properly:

	influxdb process was unable to start [ FAILED ]

but a `service influxdb status` prints

	influxdb process is running [ OK ]

Since this is only a problem on the CI (and on an ancient
Ubuntu Trust VM), I've decided to ignore this behaviour.

influxdb/influxdb-ruby,influxdata/influxdb-ruby,influxdata/influxdb-ruby