[MINOR] fixed one more error from CodeQL (#3788)

* Fixed dereferenced variable is always null

Signed-off-by: Sally MacFarlane <sally.macfarlane@consensys.net>

acceptance-tests/dsl/src/main/java/org/hyperledger/besu/tests/acceptance/dsl/node/ProcessBesuNodeRunner.java

@@ -524,7 +524,7 @@ public class ProcessBesuNodeRunner implements BesuNodeRunner {
   private void killBesuProcess(final String name) {
     final Process process = besuProcesses.remove(name);
     if (process == null) {
-      LOG.error("Process {} wasn't in our list, pid {}", name, process.pid());
+      LOG.error("Process {} wasn't in our list", name);
       return;
     }
     if (!process.isAlive()) {