Fixing error when connection does not exist

We had an error with mongo v2.4.5 on debian squeeze with node.js v0.10.10.

When createCollection was called, and the collection did not exist, we were getting a "collection already exists error".  Strange.

The changes:
* Ensure that if there is an error returned on collection creation, that error is thrown
* Creates the database connection with strict = false
* Uses collection instead of createCollection, as this does not cause the error