Setting INFLUXDB_META_DIR causes initialization to run every time the container restarts

[influxdb.zip](https://github.com/influxdata/influxdata-docker/files/1928671/influxdb.zip)

I've attached a docker compose file that both shows a system with and without an issue. To reproduce the issue:
1. Run the compose file in ./issue (`docker-compose up -d`)
2. View the logs to see everything is working fine (`docker logs influxdb`)
3. Stop the container (`docker stop influxdb`)
4. Start the container (`docker start influxdb`)
5. View the logs to see that initialization fails because it is trying to recreate the admin user (`docker logs influxdb`)
6. cleanup the container (`docker-compose down`)

If we run through the same process for the ./noissue compose file influxdb will start and restart without issue. The only difference in the compose file we aren't setting INFLUXDB_META_DIR

Compare the attached ./issue and ./noissue compose files, focusing on the INFLUXDB_META_DIR setting and the container initialization behavior. Reproduce with docker-compose up -d, docker stop, and docker start, then inspect docker logs influxdb. Done means the container restarts successfully without failing while recreating the admin user.

Written by the indexing model from the issue text.