Upgrading a node resets that node's cassandra-topology.properties

[eriksw]

Using current ccm installed via pip (3.1.4), when I upgrade a node using the following steps, the cassandra-topology.properties in that node's conf dir reverts to defaults.

ccm nodeN stop
ccm nodeN setdir -v 3.11.4
ccm nodeN start

This results in the node being unable to start, because of:

ERROR [main] 2019-04-01 14:06:34,979 CassandraDaemon.java:749 - Cannot start node if snitch's data center (DC1) differs from previous data center (dc2). Please fix the snitch configuration, decommission and rebootstrap this node or use the flag -Dcassandra.ignore_dc=true.