Remove the commented setting of "autoConnectRetry"

This option is deprecated without replacement, and doesn't really make sense: if connecting fails before
the connect timeout then it likely won't get fixed by retrying: it must be something other than just time that
prevents us from connecting.

Additionally: the connectTimeout of 15s is exactly the same time that Mongo would automatically retry (see
DBPort#CONN_RETRY_TIME_MS, which is used when #maxAutoConnectRetryTime is not configured), so the retry would never
help.
Merge pull request #375 from Collaborne/remove-autoconnectretry-comment

Remove the commented setting of "autoConnectRetry"