Change replacedIP to return external hostname 

instead of external IP. This resolves to the internal hostname if queried from inside AWS.

When using Ec2Snitch, replace node fails due to Priam sending the external IP of the replaced node as the casasndra.replace_address= option.

With this patch, Priam returns the external DNS for the replaced node, which resolves to the private IP if queried from within AWS. 

I've checked this , and it solved the problem on my setup and replaced nodes now work automatically.