Do not send ping to unbootstrapped node

Currently the SDK does not check if a node has bootstrapped prior to sending a ping to the node. This can cause a timeout for the entire ping operation (i.e. in a 3-node cluster, if 2 nodes have bootstrapped and the 3rd is coming online, there is a possibility the ping operation will timeout due to the 3rd node pending successful bootstrap).

Suggested change:
Instead of sending a ping operation to a node that has not bootstrapped, set the node state to error and indicate in the error content the node has not completed bootstrapping.