possible fix for mongo.opened function (the bug is that it replies true for the opened, but right after that the assertion during close is failed due to missing collection)
possible fix for mongo.opened function (the bug is that it replies true for the opened, but right after that the assertion during close is failed due to missing collection)


Former-commit-id: 7f6663c8fa2d82ec2d19bc1453cf07ad6659e6cf
webgme/webgme-engine,webgme/webgme-engine,webgme/webgme-engine