XD-1983 NodeExistException on ModuleMetadata write

- Ignore ZK `NodeExistsException` on writing module metadata as this
is likely to happen when the container disconnects and reconnects
but the admin leader was not available to handle the container
departure event.
  - In this case, upon container disconnect the modules on that
container get undeployed and when the container reconnects
the `DeploymentListener` makes sure to deploy the same modules
except the fact that the ZK paths for the deployment and module
metadata already exists.
Two small changes I'd like to make (with your approval) before merging:
 1. This should be logged at debug, not info 
 2. The sequence number isn't required for the logging, that's the only reason this is passed as a parameter