Clean up Mongo databases created by the test suite.

[wedaly]

Deletes Mongo databases that were being created by the unit and acceptance test suites.
@davestgermain @jzoldak

https://edx-wiki.atlassian.net/browse/TE-339

[jzoldak]

@dglance there are so many changes being made to the rake files for testing, that we feel it shouldn't be on you to keep up with them before getting your stuff merged in. @wedaly and I were discussing and maybe the best way to tackle it is for you to not worry about test tasks. If you leave the rake test tasks not deprecated on #2146 we will take on the responsibility for translating them to paver. That makes sense anyhow because then we can make sure our jenkins server does the appropriate thing.

[jzoldak]

@wedaly
Testing on devstack, I confirmed that both these worked, both with and without dbs named test_foo:

rake test:clean_mongo
mongo delete-mongo-test-dbs.js

But then when I ran rake test and checked afterwards, there are 3 test_xcontent_foo dbs remaining. :(

[wedaly]

@jzoldak I forgot that Rake ignores repeated invocations of a task unless you re-enable it. Should be fixed now.

[davestgermain]

seems like a good place to put a more general cleanup task that would do clean_mongo in addition to anything else in the future, rather than repeating this in a few places.
but if rake is going away anyway, probably not worth it.

[davestgermain]

👍

[jzoldak]

👍