MongoDB setup errors

[fernandoacorreia]

README.md has this notice:

# Most software is installed automatically by the script, but running the mongo command below from 
# the install script was causing some errors. For now this needs to be run manually.

I've noticed that some times, after restarting the client machine, the command to create the MongoDB fails. I've wrapped it in a retry loop and it ends up working, as shown:

INSTALL: Creating MongoDB database
MongoDB shell version: 2.0.4
connecting to: 10.32.0.12:27017/test
Sun Aug 25 00:44:29 Error: couldn't connect to server 10.32.0.12:27017 shell/mongo.js:86
exception: connect failed
The command failed. Attempt 2/20 will start in 30 seconds.
MongoDB shell version: 2.0.4
connecting to: 10.32.0.12:27017/test
Sun Aug 25 00:44:59 Error: couldn't connect to server 10.32.0.12:27017 shell/mongo.js:86
exception: connect failed
The command failed. Attempt 3/20 will start in 30 seconds.
MongoDB shell version: 2.0.4
connecting to: 10.32.0.12:27017/test
Sun Aug 25 00:45:29 Error: couldn't connect to server 10.32.0.12:27017 shell/mongo.js:86
exception: connect failed
The command failed. Attempt 4/20 will start in 30 seconds.
MongoDB shell version: 2.0.4
connecting to: 10.32.0.12:27017/test
Sun Aug 25 00:45:59 Error: couldn't connect to server 10.32.0.12:27017 shell/mongo.js:86
exception: connect failed
The command failed. Attempt 5/20 will start in 30 seconds.
MongoDB shell version: 2.0.4
connecting to: 10.32.0.12:27017/test
Sun Aug 25 00:46:29 Error: couldn't connect to server 10.32.0.12:27017 shell/mongo.js:86
exception: connect failed
The command failed. Attempt 6/20 will start in 30 seconds.
MongoDB shell version: 2.0.4
connecting to: 10.32.0.12:27017/test
switched to db hello_world
false
false
bye

So I think the issues with setting up MongoDB can be fixed with retries. For now I have this in a post-installation script, but I hope eventually that this can be integrated into installer.py.

[hamiltont]

@fernandoacorreia FYI, I fixed this by waiting for MongoDB to allow me to bind to the port, using until nc -z localhost 27017 ; do echo Waiting for MongoDB; sleep 1; done, in the travis setup. Perhaps we could use in the normal install setup