Disable SSL on testing old BWC nodes (#30337)

Old versions of Elasticsearch with SSL have a problem due to a bug in Netty where an illegal reference count exception can cause the cluster to fall apart. This issue impacted Netty 4.1.5.Final and 4.1.6.Final. With: $ for tag in $(git tag | grep -E 'v5\.[0-9]\.[0-9]$') > do > echo -n "$tag " \ > && git show $tag:modules/transport-netty4/build.gradle \ > | grep netty-buffer \ > | cut -d: -f3 \ > | perl -p -e 's/"$//g' > done v5.0.0 4.1.5.Final v5.0.1 4.1.5.Final v5.0.2 4.1.5.Final v5.1.1 4.1.6.Final v5.1.2 4.1.6.Final v5.2.0 4.1.7.Final v5.2.1 4.1.7.Final v5.2.2 4.1.7.Final v5.3.0 4.1.7.Final v5.3.1 4.1.7.Final v5.3.2 4.1.7.Final v5.3.3 4.1.7.Final v5.4.0 4.1.9.Final v5.4.1 4.1.11.Final v5.4.2 4.1.11.Final v5.4.3 4.1.11.Final v5.5.0 4.1.11.Final v5.5.1 4.1.11.Final v5.5.2 4.1.11.Final v5.5.3 4.1.11.Final v5.6.0 4.1.13.Final v5.6.1 4.1.13.Final v5.6.2 4.1.13.Final v5.6.3 4.1.13.Final v5.6.4 4.1.13.Final v5.6.5 4.1.13.Final v5.6.6 4.1.13.Final v5.6.7 4.1.13.Final v5.6.8 4.1.13.Final v5.6.9 4.1.13.Final We see that this means we need to not use SSL when testing nodes before 5.2.0. That is what this commit does.

Author: jasontedor

x-pack/qa/full-cluster-restart/build.gradle

@@ -163,7 +163,7 @@ subprojects {
  setting 'logger.level', 'DEBUG'
 
  setting 'xpack.security.enabled', 'true'
- setting 'xpack.security.transport.ssl.enabled', 'true'
+ setting 'xpack.security.transport.ssl.enabled', version.onOrAfter("5.2.0").toString()
  setting 'xpack.ssl.keystore.path', 'testnode.jks'
  setting 'xpack.ssl.keystore.password', 'testnode'
  if (version.onOrAfter('6.3.0')) {